From Dota 2 Wiki
Rarity is a property of cosmetic items. It is represented in-game by the item's color theme.
Rarity is a purely cosmetic property, and has no effect on gameplay.
 General Information
- Items have both a Rarity and a Quality value.
- In general, rarer items tend to have more customizations.
- The rarity of items that can drop is dependent on the player's Profile Level.
- Lower rarity items drop more frequently than higher rarity items.
- This system was implemented to reduce item farming by bots.
- Rarity does not determine whether or not an item is tradeable or marketable, Quality does.
- Under rare circumstances, an item's rarity can be changed by Valve.
|Common||#B0C3D9||The most common type of item.||1|
|Uncommon||#5E98D9||The second most common type of item.||2|
|Rare||#4B69FF||The third most common type of item.||4|
|Mythical||#8847FF||The fourth most common type of item.||6|
|Legendary||#D32CE6||Items of a special rarity.||9|
|Ancient||#EB4B4B||Items gained from special events.||11|
|Immortal||#E4AE33||Items gained from special events, as well as certain items that have been removed from regular circulation.||-|
|Arcana||#ADE55C||Items that grant heroes extensive customizations, including models, animations, particle effects, icons, and more.||15|
 See also