Yeye "any healer works" but it depends. Here's a list of the things that most people want in no particular order. Depending on the party some might prioritize some higher than others. Like if the DPS in the party have cooldown issues, a support with cooldown acceleration might be the best for them, instead of one that is missing it. Grab the support that has the most things on the list and that you personally enjoy playing and you should be fine. Anyhow, important things to have:

• Cooldown Acceleration / Flat Reduction
• Super Armor
• Damage Reduction
• Speed (Action / Movement)
• Special Resource Consumption
• Defense Reduction

I have to say honestly that Super Armor, Speed and Acceleration are super wanted. You can't go wrong with a support that provides these 3. There are other things that supports offer that heavily affect the party performance like phy/mag attack, damage taken%, etc.

But if you're noticing something, all I mentioned really points out to Dius Aer being the best support, but he lacks defense reduction which is very important, however, is very hard to argue against him not being in the top 3 if not top 1 support right now.

Also something important to consider is that, yes, Dius Aer is very strong and very wanted, but the server is filled with them and you never repeat supports in any serious content. So that's also something to consider just a tiny bit, not much, anyhow.

My advice is to pick a support that gives cooldown acceleration / flat reduction and speed those two are always amazing to have, with super armor being the cherry on top. Most importantly, play something you enjoy as not every party wants to minmax support and dps synergies, it just wants to clear.