Tools and software made by the Smash Custom Music team:

OpenRevolution: Command-line BRSTM (and similar formats) tools.
Create BRSTM files and convert them between other formats. Available for Windows, Mac, Linux.

BRSTMgram @brstm_bot: Smash Custom Music telegram bot

Automatic BARS patcher: An improved and easy to use version of the BARS patcher
that runs directly on your Nintendo Switch.

(Legacy) BARS patcher: Nintendo Switch BARS file patcher for BWAV headers
An online version (of the legacy version) is also available.

Tools and software recommended by the Smash Custom Music team:

vgmstream: Tools and plugins for decoding various Video Game Music formats

LoopingAudioConverter: Windows GUI converter for BRSTM and similar formats

VGAudio: Converter for BRSTM and similar formats

nus3audio-rs: Tool for modifying nus3audio files

Nikku: Web-based BRSTM player Various SSBU modding tools, including nus3audio and BRSTM tools