Commander X16

Deflemask Music Tracker (in Sega Arcade mode: YM2151+SEGA PCM) 

https://deflemask.com/

- maybe we can have YM2151+VERA PCM Deflemask Module player on X16

SAA1099 Tracker

https://saa1099tracker.borik.net/

https://github.com/mborik/SAA1099Tracker/find/master

- Maybe we can have SAA1099 player on X16

Lanex LNX SAA1099 Tracker

https://www.ilnx.cz/lnxtracker/install/

TILEStudio (background, sprites, maps)

http://tilestudio.sourceforge.net/

TILEStudio2

https://www.wieringsoftware.com/ts2/

- maybe we can use TS (Basic, ASM)

TilED MapEditor (map maker)

https://www.mapeditor.org/

Also here is how to load TilED map into BASIC:

https://www.commanderx16.com/forum/index.php?/files/file/75-tiled-map-editor-basic-data-export/

- maybe we can use maps in txt format

If You know other Crossplatform tools let me know!

https://cc65.github.io/ - cc65 C/Assembly toolchain for 6502 family cross-development, including support for the Commander X16

Am I allowed to self promote?

https://prog8.readthedocs.io/  cross-compiler for in-development "Prog8" language targeting 6502 machines C64 and CommanderX16