This datapack, designed for the Pixelmon Mod allows grown mint plants to additionally drop a mint seed when harvested, allowing for new mints to be planted immediately.
Since pixelmon currently has the drop hardcoded, this datapack makes use of a function to summon mint seeds to the location of dropped mint items, and then tags the mint to prevent additional seeds from being summoned. By dropping existing nature mints on the ground, you can also receive a seed (only once per mint).
This datapack was written for and tested in pixelmon 9.1.11 (for minecraft 1.16.5), and also works for pixelmon 9.2.6 (for minecraft 1.20.2).