Looking over PF2's classes I'm having a difficult time seeing if a buffer build is possible outside of bard's inspire courage, heroism, and bless. Are there some gems for buffing that I'm just missing?
I think just self buffs via defensive spells (blur, mirror image, etc.) and polymorphs. Since everything is a conditional bonus extra offensive buffs wouldn't do that much. You can't increase attributes.
You can still cast invisibility on the rogue, I guess.
E: Stoneskin can be cast on another creature. There might be other defensive/utility spells that qualify as buffs even though they don't give numeric attack bonuses.