Summoning guide for dummies?

[Tuna]

Air Queens, ice devils, arch devils, the rest of the elemental royalties, heliophagi, demon lords, in that order, imho.
Those are ofc all unique.... And they are raced for.

Of non-unique, Wraith lord and bane lord are very good thugs.
Tartarians are quite good, but you rarely get commanders/mages.
For non-commander units, enliven statues, mechanical men, pale riders and legion of wights are always good (no lifedrain).

For sc's generally anything with suberb stats, lots of slots and preferably a few resistances. For examples, refer to air queens. All they need to be really great is some prot, fire resistance and cold resistance.

For thugs, anything with decent stats, preferably decent inherent equipment (so you only need to add few items) and low price, refer to bane lord.

For troops, anything that takes long time to kill