Term: Rarity

Basic: Basic items, mostly unenchanted gear and/or stuff that is easy to find.

Common: Common items that one can make themselves in areas you'd expect and/or aren't that hard to obtain despite being standard. All creatures, items, and spells are common until said otherwise. Adds +2 to things.

Uncommon: Specialty items that isn't quite to hard to find, but requires going out of one's way to find them. Uncommon Creatures or Abilities follow in the same logic. Uncommon spells are mostly simply, but verge on Complex in some cases. Adds +4.

Rare: Rare and Abilities items are few and far between, require one to go to other places to find them if their current area doesn't specialize in it. Rare creatures are usually 1 in 100 in terms of crowd. Rare spells tend to tend to be always be Complex. Adds +6.

Exotic: Exotic items tend to be very rare, and the chance of finding them are vanishingly small. Exotic creatures and fauna tend to be folk tales outside of their common habitats. There are no Exotic ancestries. Exotic spells are abtly named, and can only be cast by those versed enough in the ways of magic. Adds +8

Legendary: Items, creatures, and abilities so rare they require long chains of adventures to find, or tend to spark adventures themselves. Tends to be on Mythic tier adventures, if not just before, when adventurers are tackling near-cosmic level threats. Adds +10.

Unique / Artifact: For items only. One of a kind. Also Adds +10 to DCs and other things that scale with Rarity.

For the full rule, see Rule: Rarity and Complexity