Second Hand Toys has some great stuff, but The Vintage Toys flickr pool is even better, in my opinion.
There's even a pool for Dakin Dream Pets, which were distributed in the 1950s. I don't know too much about them...other than...they're incredible, and could be a post on their own.
(posted to pool by glamourfae)
Lastly, check out the flickr pool for vintage toymaking books and another for vintage toy patterns.
If any of you have favorite links or photos, you should comment them over as well! I'm sure there are a ton of cool places/links I haven't found yet.