A common complaint about the support role is that the champion pool for it isn't very diverse. While that is true (at least compared with anything that isn't ad carry), it isn't quite as narrow as you'd think. Curse's Elementz plays Fiddlesticks a lot as support but we don't see many people playing him. He is not considered part of the support cast even though Elementz has used him consistently and in varying matchups.
Part of the problem that causes this is that people don't understand at a deeper level what makes a champion capable of supporting. On the surface, Fiddlesticks does not seem remotely close to Janna, Taric, Soraka, Lulu, Leona, or other typical supports, whereas typical supports commonly seem to provide armor, heal, stun, etc.
I'm going to review what a support does, attributes and abilities you want your support to have (no one has all of them), then review some of the unorthodox possibilities I've considered and explain why or why not they don't work out.
What Every Carry Wants
There's one caveat I have, and that is the kill lane caveat. You can take literally any champ in the game, have them not take the cs, and then have them try to kill lane opponents to get the ad fed. The problem is, this is a huge gamble because if you don't win the lane so hard that the other carry becomes completely irrelevant, you will automatically become irrelevant yourself late game. You might get ahead by 30 cs and 2 kills, but late game the enemy team's support will still be useful, and you won't be, and the tradeoff for just that 1,000 gold advantage on your carry is not enough to justify it.
I'll make some obvious statements to drive the point home, but they'll be prove useful later when evaluating less obvious candidates for the support position.
Defensive: Protect and Disengage
The first and most obvious set of attributes a support needs is the ability to defend and protect. Abilities that target teammates, like heals or shields, are the most obvious, but there are also knockbacks and knockups, speed buffs, or even temporarily making someone invincible (Kayle). Slows and stuns can also serve this purpose. The more a champion can keep an opponent off an ally, or stall them, or get in their way, the better.
A support always needs to have some ability to save an ally's life without necessarily having to kill the opponent. Even more aggressive supports like Leona or Blitz have the ability to do this. Doing this is what separates a support from simply a mage or fighter who happens to have a slow or stun. Sion, for example, is not a good support, though Taric is, when they have similar stuns.
Engage, Initiate, Pursue, Harrass
A support is also capable of fighting. Sometimes the best defense is a good offense. If opponents are scared of someone because they'll gradually take 1/3 or 1/2 their health in the next minute with minimal consequences, or because that person will cc them so hard that their carry will win a fight for free, or because you'll prevent them from getting out of tower range after they start a tower dive, then that is another form of protection.
Later in teamfights, it's great when a support can start a teamfight at the front line by separating/isolating an enemy or by tanking so that the other 4 teammates, all of which will deal more damage, will have more time to deal damage themselves.
In group or team fights, it's also helpful when a support helps teammates pick off stragglers. This is done using many, though not all, of the protective abilities.
Harrassing is the ability to deal damage in lane. The purpose is to make enemies miss creep score, flee upon engagement due to being behind in health, or even force a recall or get an ally a kill.
During the lane and postlane phase, buffs are casted and passive abilities that give extra stats or abilities to allied champions. Soraka gives everyone free Magic Resistance with her passive, for instance. These abilities make it so it's more likely for teammates to get the kill and not the support. If you give ap or damage to an ally, that champion is more likely to get it. This is why Aegis of the Legion, one of the best and most cost-efficient items in the game, is best on a support or jungler.
Scaling and Money
Supports can do all these things while giving the majority of the kills to teammates, without taking many creep kills either. A support can succeed while having at least 12 points in the utility tree for the gold mastery, greed, Gold per 10 seconds runes, and gold per 10 seconds items like Philosopher's Stone, Heart of Gold, and then Shurelya's Reverie. Supports need to buy wards because it's their job and you want other teammates to have more money. Using these items, masteries, and runes helps you do that. If a champion can't do well or be relevant without using these items, runes, and masteries, then they fail a basic criterion.
AND they still need to be able to help win teamfights, and not feed/melt while doing so. Janna's abilities are all useful even if she had absolutely no items whatsoever, because of what they do. Even with no AP or damage to scale them, they still do what they do nicely. Having high base values is also helpful for this reason.
Different Supports--Why Can Fiddlesticks, Yorick, or other unusual choices work?
Now to explore some unorthodox possibilities. Remember. the more of the 5 abilities that do this, the better a champ can support.
Fiddlesticks and Yorick are what we'll start with, because they have actually been used at high level play, but people still don't understand why. Fiddlesticks 5 abilities are a -10 MR to enemy champs within 1000 range (debuff), a fear, (protect / disengage / engage / harrass), drain (damage, but self-sustaining), a bouncing silence (debuff / protect / harrass), and an ultimate that deals 125/225/325 magic damage per second (and there's at least -10 MR on anyone hit), without any ap added. Drain and his ultimate are not typical support spells, but they give him something to do in teamfights and help them win, and help him survive. It also puts enemies in check--even though this guy might have no items, he'll still have that -10 MR debuff and a lot of damage. If you have to focus the support, what will happen to you in the meantime, before you even hit the tanks and bruisers? At level 5, he has a 2-second cc, and he has a silence that can hit multiple targets. Fidd's cc can have a carry down by half before the fight even starts, and then he starts draining, forcing the choice of "hit the damaging/healing support" vs. "hit the carry while this support drains me". It's range is long too, making disengagement difficult.
Now Fiddlesticks isn't the best support, but he can actually do it, and if the other team isn't expecting it or doesn't have answers, he can be a great help.
Yorick's ultimate means that even if a person gets burst down early, they can be revived for ten seconds. Or he can cast early, dealing another 55/65/75% damage of a carry's auto-attacks. If you're sieging a tower, you can literally spend 5 minutes Yorick-ulting 3-times with the ghost upfront and the mage and live carry in back, slowly chipping it down. He has an AOE slow, and his Q and E are offensive, but they make him tanky enough to go toe-to-toe with junglers and bruisers. Ghouls block skill shots and are super annoying. If you think this is easily ignored, you haven't played against it. The harrass is crazy.
Here are some other champions I've considered as supports, putting them in three categories, can, can't, and meh/maybe.
Ziggs: I tried this one for ages. In lane and even mid game he's great in jungle fights and stealing buffs and dragons. His mines take up an entire corridor in the jungle. There is no pathway they don't completely block off. And his passive is awesome harrass in lane, leaving auto-attack trades in his favor (assuming you got enough armor to start). The problem is hi Q, R, and passive are just damage, and late game they don't do enough to matter, and the mines and satchel aren't enough cc to protect. He is stuck with mid, unfortunately, which is too bad, because in lane he's really fun and he's great at preventing and initiating ganks and chasing down junglers or carries that got in too deep.
Amumu, Mao: sometimes I actually see this in ranked games and I cringe if it's on my team, because I always lose. They do have cc, but they need scaled items to be tanky in late game. Their aoe also leads to lots of creep stealing. They dive hard to get kills for their team, but they need have the extra money from jungling to be able to afford to do this. Squishy tanks end up being useless. If you think you should have them be a kill-lane, remember the kill lane caveat.
Shaco: boxes are an interesting idea, as is using clones to scout. He is also slow. Unfortunately, eh can't peel too well and doesn't scale. His mana costs are too high also. Hilarious when attempted, even funnier when it works.
Warwick: the attack speed buff is grossly inferior to Janna's shield, Lulu's shield, or Nunu's bloodboil. His skillset for durability just can't be done without some scaling. E is great for chasing, but it only helps for Warwick, not for teammates. Ultimate is nice in lane, but you just get obliterated later in the game.
Sejuani: She is actually better than the tanks I've reviewed so far as her passive doesn't cost anything, but again, she doesn't scale. Her ultimate can be done from range and is great, but her passive, Q, and E all require her to tank what she can't afford to.
Singed: passive, q, and R are nice harrass and tank stuff, but not enough to do much. It's hard to initiate with Singed's w and e when you're decently farmed. Using R to just try to get one fling is very weak initiating indeed. The E is nice for peeling, but there are champs that can do everything Singed can and more. He needs to be top where he can farm and push like crazy.
Rammus: the kill lane caveat doesn't apply as heavily to Rammus. His W makes up for lack of items and if you can get an early aegis and/or Shurelya's, you can be great at ganking mid by using Q from dragon. He is too vulnerable to harrass though, and doesn't have the sustain. He is a burst all/in champ that can't get in the Blitz or Leona can. If you actually make it late game he scales a lot better than some of these other poor supports, but he just has too hard a time in the early and mid games.
Teemo: this one is curious. Mushrooms are indeed annoying, and help provide vision on the map. Blind is nice, but that is the only supporty move he brings to the fight. He has no sustain, and in team-fights all he can do is blind and try to do damage, all while being squishy. Teemo needs to sting like a bee to be effective, be it AP or AD, and without the items, he can't do that. Once again, lane phase is where he can do something, and then afterwards he becomes too squishy.
Volibear: nice in lane. Completely irrelevant late. He'll get poked or burst down trying to initiate. You don't want a support that dies or loses half his health just to do one flip. His slow is dangerous and not ranged, his w and R are damage moves that require him to be close. Passive is not good at end-game. He's weak at top and jungle. He's horrible at supporting. I hate when I see this guy at bottom lane.
Sivir: I accidentally ended up doing this once. We won heavily. You shouldn't pick it, though she's actually in the top 3 for AD carry supports. Her ultimate helps the team a lot, including in late game. Her Q, passive, and W make for great poking and passive, even in later mid-game. Her spell-shield means she'll be even less likely to be targeted. Still, she can't protect whatsoever except from her ult. It would be fun to use her with a jungler and bruiser that benefit greatly from movespeed and auto-attack speed (Warwick, Xin, Jayce, etc) and watch the fur fly, but this isn't competitive.
Orianna: This one is really too bad, because she's almost but no cigar. Her Q lets her check bushes safely, her W can slow down or speed up, and she provides a shield with both armor and MR (it provides 30 of each at level 5, a very high amount at level 9; at level 7, it's 25). Her R will disrupt an entire team. Her passive is nice for trades/harrass in lane. Unfortunately, her mana costs are too high and she doesn't have mobility or ability to use abilities at multiple times. That ball can only be doing one thing at a time. To even reattach it for the passive costs 60 mana. Taric and Soraka provide armor and mr for free, no costs, no turning off or on.
Ashe: Niche to be sure, but she can actually scale late game, stay useful, and not die for free. Her passive is great for harrass and is a nice first hit in every fight, her bird helps with map control, which supports do, and her W and Q are crazy poke and permaslow. Her ultimate allows her to pick off and set up kills for her team over and over again. Remember how I said Janna's abilities would be useful, even if she had no items. So would Ashe's, especially her ult.
Jayce: Jayce has 8 moves, 4 of which he has access to any time. If he uses one of the free ones, he gets a small burst of speed. The free ones are extra magic damage on hit, reduced armor and magic resist on hit. His melee moves are a knockback, a slow, and an aoe damage; his ranged moves are a couple of pokes, and a shurelya's proc that is easier for teammates to make use of. He can run and chase like Nidalee, then extend that power to his team. You could seriously make a team comp based on poke and movespeed with a Jayce support, running in and out together. He can handle being next to someone with his free armor and MR in melee mode, or he can sit back and harrass from range. He's not top-tier but if the enemy team doesn't have enough engage or initiation, you can hit away their only initiator over and over again while you and your team poke like crazy until your initiator starts, and with a lead to boot.
Lux: she's not the best but I've seen her at high-elo play. Lux is hard to play, but if you land her shots she is very difficult for your opponents to deal with. Her R is great for sniping or using early in fights to help burst, and she has a slow which reveals brush, a double-snare, and a shield. Her abilities remain relevant all game.
Zyra: Free mini-wards. Can seedcheck to use real wards, seedcheck baron and dragon, burn dragon with two seeds. Her plants scale themselves with your level. Her E provides snare and slow and works really well when you're in the back (which you will be, as support). The bait potential with seeds is great--you can stick one in lane bush when you are maxed, wait 15 and put 3 more for tons of harrass. Her ult can knock up a whole team. End game, she will still be cc'ing the team and providing plenty of damage and cc. She is especially good vs. Taric in lane, when Ali and Blitz are banned, which is all the time. Put seeds in bush. If he gets even remotely close, snare/slow him or the carry. He won't get the stun off, or if he does, it won't last as long as the carry is snared.
Can Kinda Support...Maybe
Anivia: I played against this once due to some player confusion. She's got a wall, a slow, a stun, high base values, and her passive means she can all-in and die against a lane while her teammate cleans up. She's too slow for this, so it's probably not a good idea, but this is one of the better mage supports I've seen.
Lee Sin: Phil Stone is not an option for him unfortunately, but he has no mana costs and he can harrass and defend and peel like a boss. I wouldn't recommend this, but if you do moderately well with him he can stick to carries like glue, shielding, ulting with his knockback, and
Heim: again, worse mages you could have. His passive provides health regen, something that is easily forgotten. Turrets are inferior to Zyra seeds though, as they attack anything on site. On the other hand, they're permanent and you can stick one in tribush or the gank bush. Late game, you can plop two down and have them start slowing. Missiles are kind of irrelevant, but he has a blind/stun on his E.
Jarvan IV: he has a slow, a nice harrass on his passive, a knockup, and he provides attack speed in a buff. He also reduces enemy armor. He also gets free armor from one of his abilities. It's possible, but he's very iffy because he does not have the ability to escape. He can knockup or ult, but then he can't get out of it overcommits. For this reason, I hesitate to recommend him, but you might be able to do it with enough coordination and if the team comps are right.
Nidalee: Traps are nice for vision, and she does heal and provide attack speed, but she can't really protect. I know she's supposed to be considered a support, but unlike these other unconventional choices, she cannot actually slow, knockback, knockup, speedup, or stun, so she can't actually stop anyone from charging or diving. She can only heal and deal damage. This is why she's not really picked very often.
Galio: provides magic and armor but only as a buff, and it heals him, not the carry. He can protect with his slow and his speed buff, and his ult is great. Problem is that at late game he's often too squishy to ult well, and that's the most important thing Galio does. Has problems harassing too as his spells are expensive. His passive means free AP from aegis, merc's, and base stats, but it's not enough to do enough damage. Hence, he's "meh."
Nautilus: This is no secret. He has a snare, hook, slow, and knockup, and they are all easy to hit. The problem with Naut is that he needs W for his shield, which scales with health, which he needs jungle money to do. Blitz's shield is free, Leona's shield is better and she is better able to be aggressive as her Q goes through minions. Take Leona or Blitz over him. If you can't get either of those, he's not bad, it's just that Blitzcrank and Leona are better at doing Naut's job in every way in bottom lane.
Gangplank: great harrass, you can't stun him because he'll just orange (and he's the support anyway), and he can provide a movespeed/damage buff and can globally provide an aoe slow, as well as permaslow anyone he auto-attacks. He also has the highest base health level in the game at level 1, at 576. GP support is mediocre because his passive, E and R are weak protection (though great for chasing) and because he can't handle armor and heals, which is provided by common supports like Soraka and Taric, and shields can block his harrass. If they have weak shields or don't have heals at bott lane, you can consider taking him. Make sure to build him as tanky and not damage.
Protect with Honor
Before you pick some non-obvious support, remember that your job is still the same and your pick still needs to be qualified. Hopefully these points will help you to better know why most champions can't support, and what to do if somehow you get a failed trade or a doubled-pick and get stuck at bottom. Good luck carrying your carry to victory!
Old Man Eyebrows
This week's eyebrows: