MyBB Community Forums

Is there a "fast way" to delete all plugins without deleting core files? 

I don't mean disable the plugins.

Don't know what's your intention...
You can move or rename the plugins folder - so you "hide/delete" the plugins from the forum system while keeping all files.
Mind to create an empty plugins folder instead.

Nevertheless disable and uninstall the plugins first to undo all changes that may have been made to the database during installation.

[ExiTuS]