Who are the most powerful pretenders?

[K]

For Bless nations I tend to use whatever works, but Monoliths, Earth Mothers, and Mothers of Serpents tend to be my favorites.

PoD is an interesting SC, but its no better than a Dragon in the early game when you are killing indies. SC pretenders don't seem to last long against enemy nations, so I don't use them much.

For rainbow mages, the Lich is hands down the best since the other rainbows are so easy to kill. One Fires from Afar or Seeking Arrow and a rainbow Enchantress is down one from four or five paths (though I've turned a few Crones into Wight Mages).