Hey there Euman, you can get vivid pixpet eggs by using egg potions on glitched pixpets in the adventure. There's a brief tutorial in the game that teaches you how. Once you've got some vivid eggs, you can export them to your main inventory by finishing your adventure at the entrance gate, going into the adventure inventory and selecting what you want to export.

Please let me know if anything I said was confusing or if you have more questions!