WLA DX is yet another macro assembler that can program the GB-Z80, Z80, 6502, 65c02, 6510, 65816, HuC6280, and SPC-700 CPUs. Included in the package there is a GB-Z80 disassembler and few converters. WLA DX was initially programmed to compile ROM images for Gameboy, but nowadays it can also patch existing ROM images with code, and even compile program files and ROM files for other CPUs like the NES-6502, C64-6510, and SNES's SPC-700.
PopAsm is an assembler (an assembly language compiler) designed to support the syntaxes of TASM/MASM and NASM, gathering together the best features of each of them. It is intended that it will support all instructions from Intel compatible CPUs, including MMX, 3DNow!, and SSE extensions.
avrLab tries to be an complete IDE for the AVR microcontroller chips from Atmel. It offers an editor with syntax highlighting which has standard editor commands like copy, cut, paste, goto line, search, and replace. Additionally, it includes support for tavrasm (a compiler for the AVR assembly language), uisp (used for the communication to the AVR), and much more.
masmz80 is a very lightweight assembler for the Zilog Z80 processor. Objects generated contain information about global symbols, unreferenced symbols, and sections that need to be relocated, so it's easy to write code in many files and reference one project files' symbols from another. Linking these objects using included mlinkz80 produces an image ready for burning on an (E)EPROM.