SS:
Envydiel is a staple, god-tier DPS.
Awshem does solid damage while also preventing the team from dying.
S:
AwThoran is a buffer/debuffer with decent damage, but his main value is how hard he is to kill, which makes him a core unit in the Seal team.
AwFawkes also deals solid damage while buffing allies and cleansing enemy debuffs. He's very hard to kill as well, so he's played with both Lysander and in the Seal team.
Zohra protects her team, deals very good damage, and controls enemy units. She can also damage enemies even after she dies. She's usually played in her own team with allies like Shalltear, Lysander, Hyldwyn, Serenmira, Melion, and others.
AwEstrilda is a buffer who gives "shields" that work even under the Ice Debuff. She can also deal a lot of damage, especially when her SP skill is active. She's usually paired with a hero who has massive damage, such as Sung Jinwoo, Envydiel, or Sion.
A:
AwLucius is a DPS who also protects his team. He needs time to ramp up, so he's usually played with Leviathan and other heroes who help him ult. Other popular teammates include Gavus, AwSkriath, Velufira, Aurelia, Jerome, Gorren and others.
Gavus is mainly a support but is often the main DPS in his most popular formation (with Aluc and Leviathan). He reduces damage taken at the start of the fight, which lets other heroes ramp up.
AwSkriath plays a similar role to Gavus when paired with AwLucius and sometimes Envydiel. He can also be played as a DPS in some situations.
B:
AwEironn is a DPS with control. He's usually paired with Alna in the front line, but that spot is often taken by Skylan or Envydiel instead. He's gradually getting replaced in the meta and isn't much stronger than Sion in the same formation.
Maetria is an execute hero with decent damage. She's usually paired with Zohra or played in the Seal team since she has multiple lives.
AwLyca is a burst DPS/support who provides energy, shields and buffs. She's usually played behind a DD in the Alna-DD pair or in the rook position alongside Lysander.
AwSafiya plays a similar role to AwLyca , she can be played as a DPS under the Ice Debuff.
Heroes below AwSafiya aren't meta, but can still be used on weaker accounts.