WREC controls an SCPI-programmable power supply (such as Agilent E3631A) to reform large aluminum electrolytic capacitors. It was written specifically for the Computer History Museum PDP-1 Restoration Project, but should be useful for reforming capacitors for almost any old equipment, even audio gear.
XCircuit is a UNIX/X11 program for drawing publishable-quality electrical circuit schematic diagrams and related figures, and producing circuit netlists through schematic capture. XCircuit regards circuits as inherently hierarchical, and writes both hierarchical PostScript output and hierarchical SPICE netlists. Circuit components are saved in and retrieved from libraries which are fully editable. XCircuit does not separate artistic expression from circuit drawing; it maintains flexiblity in style without compromising the power of schematic capture.
YaPIDE aims to be a fully featured Microchip PIC simulator for Linux (and probably other Unixes). It is a GUI that provides a viewer for RAM, ROM, stack, breakpoints, and watchpoints, and has a source editor with inline debugging (ASM). The chip currently supported is the 16F628 (partial).
asfpga is an assembler written for use in FPGA design. It can be easily modified for a particular instruction set. The ultimate goal of this software is to allow a FPGA designer to easily write assembly code for a custom instruction set. The current version allows you to create a listing file, a memory dump file which can be used in debugging HDL code using $readmemh() or equivalent routine, and a binary file which can be used to program an EPROM.
gEDA is a suite of electronic design automation (EDA) tools. Currently, the project offers a mature suite of free software applications for electronics design, including schematic capture, attribute management, bill of materials (BOM) generation, netlisting into over 20 netlist formats, analog and digital simulation, and printed circuit board (PCB) layout.