Yes, there's a fully open stack for the Lattice iCE40s (the largest of which has 7680 LUTs):

http://www.clifford.at/yosys/ (Verilog synthesis) https://github.com/cseed/arachne-pnr (Place and route) http://www.clifford.at/icestorm/ (Bitstream generator and programmer)

I think some people had a full open source toolchain (or were close to it) for some of the Lattice FPGAs, but I think only the really feeble ones that have 10s of LUTs.