We could add many magic/holy spells. For example Holy Light [H+F] giving darkvision 50 [or at least 25] to entire army.
MA TC has some crappy summons [for example that Huli Jing]. Maybe they got better with CBM, but vanilla ones are utter crap. I hope summons here do not become like that. And if that mods is for vanilla and we make lower level summons good [especially compared to other ones] it may be really strange. So adding summonable mages/SCs may be easier to balance for standalone mod, not a part of CBM.
I can sit with encyclopedy of mythology and find summons for many nations, I guess
Though someone else would have to do stats.