Fulgore and Spinal are the obvious choices. I get the sense that Glacius players have figured out those matchups to an extent, but even then the ability to play fireball teleport shenanigans alongside strong up-close pressure still tip the matchups in their favour. Jago does alright too. People had this pegged as a slightly bad matchup for Jago, but I think the reality is that it’s a deep one with a lot of specific aspects that both sides can improve on. Shadow Jago might have a better time of this matchup, for similar reasons to Fulgore and Spinal: he can basically teleport in with a mixup, and he has a credible fireball game that Glacius players may have to respect. I can’t really speak to the rest of the season 1 cast.
I don’t think Riptor is the way to go, for similar reasons to Wulf. I could see Maya doing well, since she can cross the screen quickly and her daggers are really good, but also Glacius might be the best character in the game at making Maya’s daggers wind up at the other end of the stage. I could picture Omen doing fairly well, since a flurry of random fireballs is probably a decent way of breaking up hails and instinct armor, but also his jump might be easily sniped by a lance. Hisako and ARIA might be worth a look, though I can’t tell you that I know anything about the matchups.
So I guess the firm recommendations I can give whilst still sleeping well at night include Spinal, Fulgore, and Shadow Jago.