Named quest rewards
Although most quest-givers allow you to select one item from a randomly-generated list of treasure items, certain multi-part quest chains have a fixed list of named, pregenerated items available. Almost all such items are Bind on Acquire (disallowing exchange between characters). You won't be able to choose freely between those, since all the quest-givers replace some of those items by random ones "of equal value".
A Relic of a Sovereign Past reward items