Cult of Tarot Forum

The first and most intriguing source for very good spreads is Barleywine's blog, Parsifal's Wheel. Barleywine is amazingly creative and his spreads are unlike others. They're based on thorough esoteric knowledge, a rich cultural horizon and respect for the tarot's own voice. (Can't say it any better - Barleywine doesn't only see the cards as functional means to get an answer to a question but as interesting in themselves, that's at least my impression from following him over the years).

There are lots and lots of spreads on Pinterest, and I love cruising there, looking for ideas and inspiration.

A great treasure chest of spreads can be found on the legendary purple site, Aeclectic Tarot's forum archive.

Obviously, you don't need to own Tierney Sadler's Deck of 1000 Spreads to use the spreads on her website. (Some of my own ideas for this deck are here, they're variations of spreads...)

Please add to this list

The main site I go to is http://angelorum.co Tons of interesting articles,unique spreads,and free readings.

I love some of the spreads I just see on tumblr. (I have a special tag for them, in fact.)
There's a ton of them, and they run the gamut from incredibly detailed ones, simple ones, serious ones, and ones with names like "Am I Being A Dick?'' xD

Some great resources suggested here. I wouldn't have thought about looking on Tumblr or Pinterest, will have to check those out:)

A couple I have come across are Psychic Library and Jeanne Mayell's