Top 4 Supports to master?

Nerfs inbound

Just pick soraka into everything except blitz and collect ur freelo

Most matchups aren't very black or white, so your comfort playing a champion can mean more than the actual circumstances in which you play it. (Outside of really specific matchups like Heimerdinger vs Syndra) Nami and Sona for example have good poke, and several poke champions have unfavorable matchups against tanks because of their ability to engage on them. (taking away their ability to poke)

Support champions are often picked based on their team's needs, particularly outside of laning phase. (which that list was made around) For example, Brand, Vel'koz and Zyra can make up for the lack of AP damage in other lanes. Champions like Karma or Bard can help your team get in on the enemy team, and champions like Janna can stop your team from being gotten in on by enemy Karmas, Sivirs, or divers. Champions like Lulu, Tahm Kench, Soraka or Morgana can keep your ace carry protected, while others still, like Braum and Nautlius, can serve as your team's front line. Each champion has not just one, but a mix of strengths that makes them useful for a variety of purposes, and even past all that, you can have Support AP Ezreal or Varus carry everyone just because the player likes them.

I recommend focusing on your favorites and using them as you see appropriate. You already have a healthy mix of champions for many situations.

Thresh is much more versatile, it's better to pick Thresh in 90% of the time. But against certain match ups(soraka etc) Blitz is more snowbally.

I like to main support role and have a few lvl 5 and 6 supports I wanted to throw in my 3 cents here. Leona is very good for any bot lane with someone who needs you to lock down a high priority target. She's the bulldog of the supports, very anti Aggro if they get too close but also good on the engage and lock down if someone needs killed. Pick her into squishy targets. Thresh is good for almost any comp. some adcs don't want him (mostly varus/sivir) but he has a lot of cc in his kit and a good shield to drop down in group fights to give your ally a boost in the fight or make a clutch save. If you can learn him, he's an excellent support. Maokai is also another favorite support of mine. Not many play him as such but his kit is really good. Passive helps to sustain him in lane (since you'll be sharing the lane with 3 other people casting spells). He also has a good short range gap closer and root for high priority target nullification, a knock back on his q, long range temporary vision saplings that also chase enemies and deal damage, aaannd his ultimate reduces damage to any ally in it while active, then deals damage back based on how much y'all took when it finishes. Also too keep this post short, Nautilus and Soraka can be situationally very good picks too to learn.

I would pick into because has a longer ranged grab.

I'd probably pick over if their team has tanky engagers ( ) who I don't want to accidentally pull in to my team.

Generally I'd say is a better Support than because of the difference in utility (Lantern, hook, flay and box over grab, self speed, single knockup, aoe silence burst / random single target damage that can push). I dunno. is fun and a playmaker. I dunno.

doesn't have a ranged autoattack.

They're both going to be alright into someone like or though. Low mobility champs (hard to dodge grab) that die fast.

As someone who has lv7 Blitzcrank I have to say Soraka is one of the esiest match up.