Any suits that are only available for specific period of time.
Event Pavilion Suits & Limited Ally Cards Suits that are either always available as long as you met certain criteria, or once they release stick around indefinitely.
Fashion Battle Arena & Endorsement Queen Permanently Available Milestone Welfares (Exhibition & Level Gifts) All Free Currency Exchange Sets All Permanent Lightchase Sets Permanently Available Ally Cards NPC collectable battle cards.
Quick reference of the available Ally Cards that also pipes over to the two above hubs to include the cards that come around in Events/Lightchase or through Crafting/Gameplay/VIP Level.