We've seen colorless shards in the game for a bit now, used as rewards in the Gauntlet and in a few other events (eg: Gods of Powerslave Set dungeon), so what about colorless runes?

Basically same idea as the colorless shards but applied to runes (ie: will power up anything).

IMO it would have made a bit more sense with the recent Gods of Powerslave dungeon to reward these, rather than just with some random color runes.