Top 5 strings
1- Supergirl's b123: fast, huge hitbox, almost impossible to trade with a normal, hit confirmable, barely whiff punishable, auto footsies at it's finest.
2- Superman's f23: Fast, easily hit confirmable, leads into big dmg, the big potato string of the game.
3- Manta's f213: huge footsie tool, hit confirmable, leads to good chip dmg and good dmg, catches backdashes, breaks armor, and is staggerable.
4- Batman's 223: lol just do it.
5- Aquaman's b123: it is still really good, even tho most people dropped him now that he is honest.
Honorable mentions:
Red Hood's b23
Batman's b23 and b11
Sub's f22
Atro's b23 and f22