A Fistful of Denarii has a fair number of feats, including Long Shadow.
The Feats Reforged series introduces the idea of feats that improve over time (usually 7th and 14th). I use those.
Other Rite Publishing feats are scattered across many products, and not just in one place like 101 Feats. Every race guide, class/faction guide and other Rite Publishing supplements include feats along with everything else.
Here's a link to d20pfsrd.com list of all posted Third Party feats.
If you play mythic games, the Mythic Hero's Handbook has a truly incredible number of mythic feats.It's over 1,000!!!
Not enough. To be truly Mythic, it has to be over 9000! We need more mythic feats!
Since I develop the Kaidan setting of Japanese Horror (PFRPG) which was published as an imprint under Rite Publishing, I submitted all Kaidan material to d20pfsrd.com
But you're right most publishers don't submit there mechanics to that site.
Many/most publishers offer feats, while some can be found in feat only supplements, like many of mine they're added mechanics to products with a feats as only a small part. Too many to identify all those possible products.