The number of unique luxury resources available is dependent on the galaxy size. You can use the same luxury for multiple levels of system development, but you cannot use the same luxury multiple times for the same level. When used for system development, the number of luxuries used, and their typical effect, is based on what tier the luxury is: Common luxuries are available at the start of the game, whereas Uncommon and Rare luxuries are revealed upon reaching Tier 3 and Tier 4 of the Science and Exploration tree, respectively.
There are three tiers of luxury resources.
They provide passive bonuses to the planet they are found on, can be spent on system development, boost population growth, and can be involved when dealing with minor factions. Luxury resources are a type of resource that can be found on planets or acquired through trade.
