Which modules are available for HP-41X?

Internal modules:

CCD ROM (pages 3 & 4)
Timer Module (page 5)
Helios Printer (HP82143A) Module (page 6)
HEPAX Module (page 7, four banks)
XF/XM Module (interchangeable with Timer Module on page 5)

HP41Z modules:

ADV: Advantage Module (fixed to pages 12 & 13)
CARDR: Card Reader Module (fixed to page 14)
EXTIO: Extended I/O Module
FINAN: Financial Decisions Pac
GAMES: Games Pac
HELP: Helios Printer (HP82143A) Module (fixed to page 9)
HPIL: HP-IL (HP82160A) Module (fixed to page 8)
MATH: Math Pac
PILP: HP-IL Printer (HP82162A) Module (fixed to page 9)
PPC: PPC ROM
RAMB: RAMBOX Module
SANDM: SANDMATH 3 ROM (8K)
STAT: Statistics Pac
STD: Standard Applications Pac
XFXM: Extended Functions Module
XR41: HP-41X Extended ROM (fixed to page 15)
ZEN: ZENROM

Other modules: (can be loaded individually)

41Z: Complex Number Module (8K)
41Z2: Complex Number Module 2 (8K)
ADVAPP: Advantage Applications Module
AECROM: AEC ROM
ASTROROM: Astronavigation Module
AUTOSTRT: Automatic Start/Duplication Module
AVIATION: Aviation Pac
CIRCUIT: Circuit Analysis Pac
CLINICAL: Clinical Lab and Nuclear Medicine Pac
DATAACQ: Data Acquisition Module
DAVIDASM: David Assembler (8K, with labels)
DEVIL: HP-IL Development Module
DUTCH: Dutch ROM
EPROM: EPROM Module
ERAMCO: ERAMCO Module
ESMLDL: ES MLDL Module
ESRSU: ES RSU Module
EXTIL: Extended IL Module
HELM: Printer Module for use with HP-82143A Helios Thermal Printer Emulator
HOMEMGT: Home Management Pac
LANDNAV: Land Navigation Module
MACHINE: Machine Design Pac
MCEPROM: MCEPROM Module
MLDL: MLDL Module
MLROM: ML ROM
NAVIG: Navigation Pac
NFCROM: NFCROM Module
PARIO: PARIO Module
PCODER: ProtoCoder Module
PETROL: Petroleum Fluids Pac
REALEST: Real Estate Pac
SANDBOX: SANDBOX ROM (4K)
SANDBOX2: SANDBOX 2 ROM (8K)
SANDMATH: SANDMATH ROM
SANDMTH2: SANDMATH 2 ROM
SECURITY: Securities Pac
STRESS: Stress Analysis Pac
STRUCTA: Structural Analysis Pac (A)
STRUCTB: Structural Analysis Pac (B)
SURVEY: Surveying Pac
THERMAL: Thermal and Transport Science Pac

Very important: I haven’t thoroughly tested most of those "other" modules, so there is a chance that some particular module (especially bank-switched ROMs and ones dealing with microcode) won’t work correctly with HP-41X. I don’t take any responsibility for this, neither I have any obligation to modify them to work with HP-41X or to modify HP-41X to work with these modules. In other words - if they work then OK, otherwise use them at your own risk and don’t ask me anything regarding the non-working modules.