Bread, bundles, eggs and events all point toward collection
The reliable starting point is simple: play rounds and complete quests or achievements for Bread, then use Bread to unlock accessories and bundles.
Accessories are the game's main customization layer. The official description says there are more than 300 unique accessories and billions of possible look combinations. It also says those accessories can be unlocked, traded and collected.
That does not mean every item has a public rarity, price or performance effect. Until an item catalog is available, use the in-game preview and requirement shown for your current version. Treat this page as a map of the collection systems—not a claim that every accessory has been cataloged.