Thinking of Suikoden Tierkreis. Assuming that Tsundere = increased stats.

Neon (Support Star)
Passive Ability: Increase tendency to Tsundere.
Active Ability: Enable
When Neon is in your party, random maps appear more frequently with treasures within.

Billy (Active Party Member)
Passive Ability: Moe Finder
Active Ability: Berserk
When Billy is in your party, no law enforcement officer will stop you, even if you are robbing them blind (including swindling them).

Juufan
Passive Ability: Multiple Personas
Active Ability: Organiser
When Juufan is in the party, more random NPC quests will open up. Note that if Neon is in the party, Juufan’s tsudere meter will increase.

Shiro
Passive Ability: Tsun 100% in random battle
Active Ability: Return to Town for free anytime
When Shiro is in party, all stats are boosted by 10%. Tsun 100% activates randomly in battle more often with Neon around.

Sairenmizuko
Passive Ability: Goal focused
Active Ability: Fangirlism
When Sairenmizuko is in the party, all quest goal markers are activated. Note that Sairenmizuko is the only member who is NOT affected by Neon’s Tsundere effect.

Sringangel
Passive Ability: Flip Table
Active Ability: Heal 100%
When Sringangel is in the group, all injury damage is lowered except in the case of Fangirlism mode. Then Sringangel receives a boost to stats but suffers from higher injury. Note if Billy is in the group, chances of random injuries to Sringangel will increase.

Tibbar_deGniw
Passive Ability: Horrify
Active Ability: Summon Tenta Bunnies
When Tibbar is in the group, chances of enemies being dismembered violently (and thus unable to resurrect) increases by a factor of 5. However, whenever not in battle, Tibbar resumes a pet-like form that makes it easy to carry her. Normal carriers include Naoko and May.

Annachuu
Passive Ability: Fangirl Pika
Active Ability: Polite Reasoning
When Annachuu is in the group, party gets discount at all stores. However, note that chances of encountering the rabid fangirl mob increases as well.

[To be added]