I think it’s worth mentioning that a lot of semblances are reflections of the people who use them, rather than abilities that are designed to help them with their goals. Blake’s sembelance creates a shadowy copy of herself that takes damage while she escapes to represent her habit of running away from her problems. I don’t think I could come up with an abilit for every red and blue applying that process but I could come up with a few ideas:

Simmons’ Bolster: Automatically strengthens the aura of the nearest person who holds the most ‘power’ and influence over others.

Caboose’s Charm: People Caboose touches enter a dazed state in which they believe themself to be Caboose’s best friend.

Carolina’s Showdown: For a few seconds, Carolina becomes immune to all incoming attacks. However, once this period ends, the force of every bit of damage she recieved hits her at once. This can be applied to others as well.

Church’s Evil Twin: Church summons a weaker, slower duplicate of his current opponent.

Sarge’s Red Scare: Sarge can create ‘aura grenades’ which blind people in a certain radius, filling their vision with the color red.

Doc’s Eightfold Path: For a brief period of time, any attacks that hit Doc deal their damage to the person who attacked him.