[Edi]

In the unmodded game, the drakes are pretty useless and have a high summoning cost, and the corpse men are just an atrocious waste of air gems even with a lightning rod.

Almost all death summons that summon low level corporeal undead (longdead, soulless, ghouls etc) or the incorporeal undead (shadows, shades etc) are bad.

My own summoning list is also rather limited simply because there is no cost effectiveness in summoning otehrs units. I tend to play with a fairly low site frequency on large maps, so you need to be economical with the gems.

Edi