Overall, what are all the little things that are already in ESO?
-lycanthropy
-vampirism
-no player housing
-synergies

Any others?

http://tamrielfoundry.com/development-faq/

It's kinda out-of-date on somethings, but it basically has everything we know of so far.

Thishttp://www.gamesas.com/topic/1443440-the-comprehensive-eso-mechanics-thread-100-sourced-information/ has a lot of stuff we know, too