Like the shaman skill trees, except they give you meta perks that let you play in your favorite role more often and/or for more rewards (sometimes at a cost) instead of in-game skills!

Due to the power of these perks, they would cost a LOT to reroll, only be rerollable every 6 months-ish, or maybe be impossible to reroll at all... but you can turn them on or off like skills so you can play normally if you want.

Examples of possible specialties:

Shaman Tree:
Independence - You never get dual-shaman maps as shaman.
Spiritual Success - You get extra points on the scoreboard for every 8 mice saved as shaman.
Grace Against Time - You get more shaman and no-skill coins, but you can only build for the first minute of each round.
Embargo - Mice can't spawn objects while you are shaman.

Racer Tree:
Photo Finisher - Times within 0.1 seconds of first place count as a first, in rooms with more than 15 mice.
Marathon Runner - You get extra points on the scoreboard for finishing in top 3, but lose points for dying.
Soulbound - If your soulmate finishes first, you enter the hole instantly and get a first too. Your soulmate gets notified if you have this perk.