I don't think there is a list yet - I can't find lists of much of anything, so been trying to cobble some together for various things that I can post. Couldn't even find one for challenge locations (though I did find mynock ones, just haven't done them yet). Trying to figure out what unlocks what has been a crapshoot.
So far, I've just been redoing the main Takeover missions on the increasing difficulty to get the feats, and find they drop a lot of the high-end gear. Plus, they get easier once you know where all the loot is hidden to make sure you get it all.
I haven't yet found anything other than the standard watering can and hoe, curious how many different ones are out there and if they just randomly show up in the chests like everything else or not.