Because the Hackslashmaster has a fascinating article on the Ecology of the Hydra, I realized there was a little bit of lore I had forgotten to contribute. Hydras are the fantasy universes pre-eminent bankers, since their heads and profits always grow back, even if they have to take a cut to their portfolios.
Generally, I have to admit the crowd-sourced Ecology series of posts is absolutely fascinating and a gold mine of ideas for the lazy dungeon master. I think collating them into a nice couple of .pdf files would be pretty cool. Nudge, nudge.