Just look at this massive list of pets. Not surprisingly, a lot of them come from the rare spawns on the Timeless Isle as well as other sources. These are just the ones I’ve collected so far, the rest of the images will be added over time.
Interact with the Neverending Spritewood (purple rare spawn crystal) and kill Scary Sprites (note these are the larger sprites which can randomly spawn as opposed to the smaller Angry Sprites) – (45.4, 73.3)
Drop from Imperial Python
Drop from Gu’chi the Swarmbringer
Gulp Froglet – Drop from Bufo
Jademist Dancer – Drops from Jademist Dancers
Jadefire Spirit – Drop from the Spirit of Jadefire