If you're looking for just stuff inspired by Lego bricks I wrote up a .txt file a while ago, but didn't get around to making it look nice and providing descriptions and pictures of all the bricks included... I was meaning to create a topic that asked if there were any I was missing but I didn't ever get around to it. There's probably more out there but here are some good ones.
They go by the names of the .zip so you'll have to search the forums here to find links. Most of these should be easy to find if you search their filenames but you might have some trouble, If you get dead links you can try the
RTB Archives but be warned you can't use the search function so you'll have to get at them manually by going through the pages of bricks and searching with ctrl+f for their filenames or something close enough, and also keep in mind some of these were released after the RTB shutdown, so you can only find them here.
blockland lego bricks
brick_windows by Tophius. includes: bay windows
brick_grillplate by Polymer
brick_corner by ChristopherP and King Tinks
brick_invertedcorners by Space Guy
brick_tiles by Jaydee. includes: various smooth tile bricks. can be recreated with prints
brick_round_corners by General and Tophius
brick_2x2fRoundPrint by Space Guy
brick_fence by General
brick_plant by General and Tophius
brick_Domes by Phydeoux
brick_legochair by Phydeoux
brick_1randompack by FART and King Tinks. Includes: a mixture of recreated lego bricks and some originals for building convienince. some essential, some not.
brick_interactive by General and Tophius. includes: various doors, containers and levers.
brick_legocrates
brick_road_sign by Barnabas
brick_extraArches by General and Tophius
brick_horizrounds by Siba and Pass
brick_wedge by Tophius
brick_FobWindow by ???
brick_coffeemug by Marcem
brick_faucet by Phydeox
brick_Goblet by Marcem
brick_log by Siba and MasterLegoDude
brick_MiscellaneousPack by Sumz
brick_Stairs by Siba
brick_VertRound by WhooMan and Rallyblock
brick_Vehicles by WhooMan and Rallyblock
brick_Odd by WhooMan and Rallyblock
brick_medieval by WhooMan and Rallyblock