I’ve found this to be the best gacha setup for crystal collection. 2 gachas, one snow owl, one pegomastax with crystal collection turned on, and a rock elemental to feed them. Being able to drop stacks and stacks of stone for them to pick up and eat will have crystals falling every couple of minutes. I have multiple setups like this around my base perimeter and can basically refill most resources vaults without ever having to leave base. Feed them EVERYTHING though as well. They’re great for being trashcans for low lvl weapons and armour, blueprints, spoiled meat, seeds etc.