I'll try to name all the passive supports: Janna, Soraka, Alistar, Taric, Tahm Kench & Braum.
Janna - Janna is the Queen of peels. In my eyes she is the best at it. You pick Janna to counter hard engagement comps and when you need mobility and range over tankiness. Janna is very hard to play aggressively. In laning phase she wants to set up a "farm fest" style lane. Her shield will shield some of the damage you take but also increase your AD. If she shields you that means she wants you to make a trade or she is countering an enemy initiated trade. Her shield has low mana costs. Her tornado has high mana costs. The tornado can be used to poke and engage but its so easy to dodge and deals poor damage for how much it costs that using it this way is not advised. The best way to utilize a Janna in lane is walk up, get shielded, land 1-3 auto attacks/abilities and then run back towards Janna. Janna's passive grants a minor speed boost so its enough to allow the enemy to be unable to catch up with you if they do try to pursue. If they line up Janna can tornado the pursuers and allows some more follow up poking. If they continue to pursue a Zephyr on a key target and another shield to soak up any poke damage to cover the retreat. Congrats you won the trade handily. And when it's multiple engages on all sides Janna can ult and everything is better now. Janna COULD use her ultimate to split up the enemy team by flashing in but that's a grievous missue of her ultimate as the heal is often wasted and Janna is in a very vulnerable position. Definitely a last ditch move on her part. Mid and late game Janna is elusive and favors split pushing and besieging compositions. She counters assassin champions pretty hard as well as hard engagers. Janna is still pretty squishy so she will try to be in the back or the middle of her teammates.
Soraka - When you have a Soraka she will try to stand behind you and out of the action. If you take any damage she will simply heal it back up. When you have a Soraka protect her, the enemy team will actually focus her if they're smart so what you want to do is farm away and poke the enemy team down. You should not go in expecting kills with a Soraka, but rather try to outlast the enemy team. If they backed before you did then Soraka did her job. You still need to focus on positioning properly. Soraka doesn't have a reliable peel in her kit. She can remedy any poke damage you take via her heals but if you position poorly and get bursted down then there really isn't much she can do besides throw down her silence pool and hope for a root. Mid and late game she will try to multitask by running between allies and healing them back and forth. She will attempt to stand in the heart of the team's formation so as to best reach everyone. Occasionally call down a starcall when the enemy bunch up so as to heal herself and slow down the enemy so that teammates can follow up with a poke.
Alistar - The king of disengage/counter engage. If the enemy has a hard engage comp then Alistar is possibly the best if not second best choice for supports. He counters people like Leona, Thresh and Draven quite nicely. In the right hands he is very disruptive. Alistars in the laning phase rely on you to initiate damage/trades a lot of times. They can initiate but often times they do so without having a good escape path and thus take serious poke damage when they try to get back to you. So ideally when the enemy duo tries to group up and match your trade Alistar will move in and headbutt one of them to separate their team. You should now win the trade as Alistar displaced one of them out of the picture. Alistar is all about getting the enemy laners off you. If he can grant you a kill that's cool too, but not his main priority. He can heal up some poke damage but not a whole lot through his heals. Poke damage is his bane so he will try not to stand too far up and will instead be opportunistic with his engages/disengages. Mid and late game he is much stronger at. He will excel at peeling engagements off his allies and his ultimate is a serious boost to his damage output and damage threshold. He will want to put himself in a position where he gets focused. While the enemy team is focusing down Alistar, Alistar is praying that his teammates will follow up and burst down his attackers. But the enemy will be taking much more effort to kill Alistar with his ultimate up so they may blow some key abilities on him when he does this. Probably his best use of his ultimate is sieging and backdooring turrets with allies. The increase in AD and damage resistance (I think it's 70% which is ridiculous) really helps in taking down a crucial objective.
Taric - Or as I like to call him "Sir Taric the gay." Taric is not a very flashy champion. Because of this many people underestimate what he can do. Taric is actually a pretty good zoning champion. His armor aura and heal help him to soak up some small amounts of poke and chase the enemy away. If they try to engage of misposition he will stun the enemy in question and hope his ADC follows up. Taric is quite manly in how he supports. He will run in taking all the damage and then heal up the damage done to him. When he catches up to his target he will smash his gems on their face and just start bashing on them. With the enemy armor shredded now is the time where you want to trade. The down side is that Taric is much squishier for this brief period of time so he will need your help to burst them down before they burst him down. Offensively, in the laning phase Taric will attempt to zone out the enemy, purposely taking damage from abilities and will then heal through the enemy poke and just be a wall that they cannot get past. His ADC can now move up and free farm to their wishes. If the enemy engages on Taric, Taric's ADC moves up and bursts them away. Mid and Late game Taric functions kind of like Alistar. He will ult and get focused all the while hoping his teammates focus the correct people. He tends to stand in the middle/front of team fights and will send back a dazzle bolt if anyone tries to bypass him and get to his ADC. Not really a great support at the moment, needs that rework desperately.
Tahm Kench - Tahm Kench is a great choice for when the enemy team picks a solo burst Assassin such as LeBlanc or Rengar or Talon. Just eat up his ADC and they're safe. In laning phase Tahm Kench likes to zone out his enemies. Because he becomes incredibly stronger when he gets 3 stacks of his passive most enemies will try to make short engagements on him. Tahm Kench is great at sustaining through enemy punishment via his grey health ability. He can poke the enemy a bit but due to its mana costs this is not an efficient or sustainable strategy. Tahm Kench can spit out minions to poke and can even extend his reach on the minions via tongue lash but mana costs are high for doing this. Tahm would much rather eat his ADC and tongue lash away any pursuers. Mid and late game Tahm Kench favors split pushers and his ultimate can work as a great repositioning/escape tool. Can also be used to chase for a kill but much like Janna's ult being used offensively this is ill advised as Tahm Kench is fairly immobile without it.
Braum - Braum is a good choice against long ranging and skill shot-centric champions. Ezreal, Caitlyn, Varus, Ashe, the occasional Twisted Fate and Nidalee. Braum's signature move is his shield which blocks skill shots. The speed boost is interesting on him. When in the front lines Braum usually uses it to get back to his ADC, opting to retreat. When he uses the shield after jumping onto his ally and he is right on top of his ally he will often use it and charge in as his ally is in prime positioning to follow up on the enemy. Braum is fairly mobile for a support but needs the presence of allies around him to give him this mobility. He is a counter engager where if the enemy moves into his minion wave he can jump right next to them and attempt to stun them via his concussive blows. When he gets his ultimate Braum can initiate and peel and disengage, but positioning still dictates what he can and cannot do. Like most of the supports on this list Braum will seek to stay in the middle of his team so that he can jump in multiple directions and can block for multiple teammates.
