Master Glyphs is level 60 level cap term for the most powerful glyphs any character could get. Uncommon glyphs have a green triangle in the upper-left corner.
Since TERA: Fate of Arun upgraded glyphs drop as boss rewards from Sabex Armory and Macellarius Catacombs. Those dungeons drop random Khirian level 58 to 60 level glyph boxes (equal to old master glyphs) and single Vanguard level 65 glyph box. Same glyphs can also be bought with a Glyph Token from Vanguard Initiative merchant.
Rare level 65 glyphs have a blue triangle, and can be obtained from glyph boxes bought with tokens earned doing repeating Island of Dawn Vanguard quests.
Awakening quest gives single superior (yellow triangle) glyph for each class.