Provides a way to quickly choose a sound from your library, even if you have many items. In my case, this is 700+ at the time of writing. It has an overlay, that works in-game (requires Windows 10), and its fully controlled with keyboard. You don't have to alt-tab out of your full screen app.

Supports any sound file, that Windows Media Player supports, usually .wav, or .mp3.

It can connect to the Twitch channel points API, if you want to allow others, to use the soundplayer functionality as a channel point reward.

It has it's quirks and limitations, but it gets the job done.