My favorite is Psychotroid with Magimites (or other CC specialists + PREY) OR Spawn… Man those are nasty combos.
I remember when I moved a Tunnel Runner (shooting with prey at some Marauder armoured dudes), then activated Terror and pushed him forward. Then next activation I hit both my units with Invigorate and both my big units were in combat the same turn (Tunnel runner with a wounded, preyed model and terror in Marauder’s deployment zone vs some snipers). It was TURN 1 
I did similar things with Nameless. Was in CC with my Magimites. Attacked Terraton in CC, then I pushed it out of the cube with my SPLAT, attacked it again (+1 for wounded). I pushed it into a cube with another Magimite
In the same game I have pushed another terraton away from my Bathomite who then clear shot it and then engaged. Nameless pushing units around is SO fun. Especially when You friends play elite lists. It does not work that great vs swarmy stuff.