Add several new never-randomly-generated cards, all of which are designed to give strong but short buffs, to you and more often allies. Though their frequencies are 0, they are sometimes dropped from monsters you and your pets kill, at the same frequency the keyed create monster cards do.

Other roles can write these scrolls if they want to or find them in bones, but they are generally intended to be less powerful than many existing scrolls so they shouldn’t steal generation probability from them.

Spells whose main purpose is to buff allies within an area of effect. (They will give the player the buff too, but the buffs won’t be a huge improvement for a single creature. So you get more out of the effect the more allies you can affect with it, and it’s best used when you have allies around).

Assuming monster casting has been expanded somehow to include ally buffing: an orc shaman can generate with a group of other orcs.

Monster spell (or song, for bard-patch variants) that temporarily causes allies to grow up by one growth stage, regardless of its level (e.g. a little dog under this effect will become a dog, a demilich will become a master lich).

Bards as a monster, who spawn in a group of same-race monsters with a (sometimes but not usually) magical instrument, and they keep their distance and play songs to buff their allies.