She only buffs other dragons. Kolaghan's the closest you can get on a legendary, unless I've missed one, since he has basically the opposite effect of Lathliss; instead of giving dragons +1/0, he makes each attacking dragon give everyone +1/0. His does need a lot of dragons to really get big boosts, but it wouldn't be too hard to have him buff up a bunch of goblins if you're willing to dip into a goblins+dragons deck.