I don't think there is a need for any of the others just now (and I don't want to flood the tactics section). I will create Psychology and Terrain threads if people have found particular problems with them (and make requests)... but I've not heard many people have problems with either. The hardest part of terrain is just reading what all the pieces do... though it would be great to see random tactical pieces/tacticas on how to best use different/specific pieces of terrain.
I won't make a non-gunline empire thread since its mostly covered by hordes, same with unstoppable magic... what tactics there are are mostly covered in the Teclis
thread, since he is the origin of 90% of unstoppable magic in the game.