There are cracked versions of Viewlogic 4 / LCA and XACT 5 out there.
VL4/LCA was a Xilinx-special crippled version of VL4 (a £20k product back then) which would import only Xilinx component libs. There were a few things like a 74HC74... There was also a program called sneaky.exe which Xilinx wrote which IIRC patched the schematic file so the full version of VL4 could open it. I had that also but never found out how it worked, and never had the full VL4.
This dates to c. 1995-96. Both used its own dedicated dongle and these were patched by a Russian coder. The crack was done because later versions of Xilinx software would not import projects done with these, but when the dongles broke (they were flimsy parallel port ones) Xilinx refused to support the product, saying "no more dongles available".
The stuff worked only under DOS 6.2. It was never tested in a Windoze DOS box. For best results it needed an 8514-emulating video card; then you got a nice 1024x768 display.
I know these cracks escaped into the wild and the above posts may be the same thing.
There are also patching programs, dated 1998, for XACT 6. WOW - 24 years ago. We were all young then
PM me if you want to know more.
I dropped out of FPGA design consultancy c. 1997. Got sick of the vendor behaviour. It was OK if you were paid for your time, working for someone else, and didn't have to care whether the project could be maintained into the future. Also most FPGA projects can be done with a fast uC.
IIRC, Foundation came after VL4/XACT. The package (which I still have) supported XC2k, 3k and 4k).