I think it was already mentioned, but I'm too lazy to look: Stitched Reconstruction effect. Love that thing.
I really want to start using Geomancer again but he just takes so much effort and support to pull off a solid Shockwave and you end up just doing a lot of damage but not enough to kill anything.
The resistance: hyeanid and elemental look really cool when one of thier effects activates. Also any other effect where tons of units appear like hippo stampede. As for sound: i like that deep "huaggh" sound some FW casters and spells occasionally make.
I like the groble dervish autoattacks, sad he isnt worth running really so i could see it more often, or he is but if those autoattacks did rend/sunder like it looks like they are, he would be awesome
Retribution....that results in a shrine kill. I once flipped a coin and it landed upright....still not as satisfying.