Plug ins

Pls check out

• available plugins Download > Plugins at the top
• filter them by Category:Playback, quick link for musescore 3 https://musescore.org/en/plugins?category=265&compatibility=4321
• also see list of built-in commands which you can assign new keyboard shortcuts to https://musescore.org/en/handbook/4/keyboard-shortcuts

However, if by plugin you mean steinberg's VST https://musescore.org/en/handbook/4/working-vst-and-vsti , you might get more input by reposting at the Playback forum