Leonardo Spectrum
- A synthesys tool, which will optimize your ASIC/FPGA/CPLD design. Evaluation license is available.
- http://www.exemplar.com/leonardospectrum/

VHDL Simili
- A fast VHDL Compiler/Simulator [Freeware].
- http://www.symphonyeda.com/products.htm

Synopsys Logic Synthesis
- VHDL Compiler
- http://www.synopsys.com/products/logic/logic.html

FreeHDL
- Project to develop a GPL VHDL simulator for Linux.
- http://www.freehdl.seul.org/