To fill your collection quickly, you don't need to keep every pet. Once a pet has been in your inventory once, it is permanently recorded.
Spend some time hatching cheaper eggs from early worlds to quickly check off common, rare, and epic pets. Pet Simulator X | Auto Pet Collection
Visit the Trading Plaza and look for players selling cheap pets you don't have yet. Trading is often faster than hatching for specific missing entries. To fill your collection quickly, you don't need