Pixelmon Plus 1.9.1.zip is a release file of the Minecraft resource pack Faithful Sounds (old sounds for Pixelmon), made for Minecraft 1.12.2. It was published on October 25, 2021 and is 121.1 MB in size. For the full description, screenshots and every other version, visit the Faithful Sounds (old sounds for Pixelmon) resource pack page.
How to install: Put the .zip into .minecraft/resourcepacks (do not extract it) and enable it under Options → Resource Packs.