AHDL - Altera's HDL.
Meta Description: [ Altera offers users design examples for use in designs for Altera devices. ]

bluespec - Bluespec adds extensions on to System Verilog to raise the abstraction level for complex control logic.
Meta Description: [ Bluespec, Inc. manufactures an ESL synthesis toolset that significantly accelerates hardware design & reduces verification costs. ]

handel-c - A variant of C, handel-c is a behavioral language for FPGA design.
Meta Description: [ High performance Electronic System Level (ESL) design solutions for; Accelerated Computing; Electronic System Level (ESL) Design; Multimedia Video and Imaging; programmable semiconductor design; C synthesis; behavioral synthesis for SystemC; and co design technologies for FPGA, Structured ASI... ]