dZ80
Is a freeware Z80/Z180 disassembler for binary files, such as arcade machine ROMs, Z80-based personal computer snapshots - DOS(source available) and Windows versions, by Mark Incley.
Utility3
A screen-resident Z80 disassembler based on an Amstrad CPC128, by Geoff Wearmouth.
Z80 Software Development Tools
Many Z80 disassemblers by Thomas Scherrer.