Advice for making a strong tournament level team

I have been playing this game casually with friends, but I was wondering how to find meta teams compositions for specific characters I like, so I can save for them.

Specifically:

X-Men, Cyclops, Emma Frost

Guardians , such as Groot, Rocket

Or Daredevil, Blade

I am used to playing Warhammer where there is no rarity scale.