These tools (currently) can only convert files from Nintendo Switch formats into more easily usable ones. They cannot convert back to Nintendo Switch formats.
Note: These tools were each made for some of the Nintendo Switch games MK8D, SMG1 (in SM3DAS), SM3DW+BF, SMBW, SMM2, SMO, TOTK, and BOTW. They may or may not work with files from other games or consoles.
YAZ0: amnoid.de
SARC: Custom Mario Kart 8 Wiki
RARC: Custom Mario Kart Wiiki
BYML: ZeldaMods
BCSV: Luma's Workshop
MSBT: ZeldaMods
BMG: Luma's Workshop, Custom Mario Kart Wiiki
BARSLIST: Nintendo File Formats
Credits: These are the pages I used to create my binary file parsing library stored here (/libs/filebuf.js).
Floating-point number parsing: An article in Medium's TDS Archive written by Oleksii Trekhleb
Signed integer parsing: Sonoma State University CS Linux Server