Rotting Regisaur has replaced Heir in my 540 cube. Cryptbreaker has been fairly decent, seeing slightly more play in aggro shells than combo... I also like but don't have room for Miasmic Mummy as a flexible option between a one-time discard enabler and value/disruption (more in pauper, especially if you support white or blue blink).
Yawgmoth and Rankle both cost 4, so very much too slow for combo-style reanimator, but can help with a value-recursion strategy.
Ransack the Lab is a great filtration effect and should be played in more cubes than it currently is.