Gonna provide a general guide here.
All Hero Attacks Involving Slows
Miguel:
•Blue Skill, 60%, Removed on white skill
Elastigirl:
•Green Skill, 25%, 3.5 seconds
Stitch:
•Green Skill, 20%, 10 seconds
Judy:
•White Skill, 80%, 3 seconds
Olaf:
•Purple Skill (Triggers After Freeze), 15%, 4 seconds.
Hiro Hamada:
•Green/White Skill, 40%, 5 seconds.
Yax:
•Purple Skill, 10%, 10 seconds.
Barbossa:
•Blue Skill, 90%, 1 second
Vanellope:
•Green Skill, 25%, 3 seconds.
Mad Hatter:
•White Skill, 50%, 8 seconds.
Finnick:
•White Skill, Stuns slowed enemies, 3 seconds
•Purple/Blue/Green Skill, 40%, 12 seconds
Alice:
•Green Skill, 35%, 6 seconds.
Elsa:
•Purple Skill, Deals more damage to slowed enemies, 50%
Possible Good Pairs/Teams
Elsa + Most: Elsa is well known for her decent damage buff to slowed enemies, which comes in handy, as Elsa deals pretty high damage to enemies alone even without her damage boost. But, this makes her highly compatible with heroes like Miguel, Mad Hatter or Finnick, a few examples who have some of the longest slow lengths of the roster, which is mainly effective because there’s a 50% increase no matter how long the stun is, making her not great to pair with Barbossa, who only slows for a single second.
Gonna add a little later.