Audio plugin add-ons not listed
Install audio software from flathub. Any of these:
org.ardour.Ardour
io.lmms.LMMS
org.musesequencer.Muse3
org.nongnu.gsequencer.gsequencer
(there are other)
Software should offer to install add-ons for it. Since these are Linux audio plugins in specified format, they are on the following "namespaces":
org.freedesktop.LinuxAudio.Plugins.*
(updated to be current with 20.08)
The supported extensions type are listed in the manifest / metadata.
This should result to the same is it does with GIMP.