Ogre Magi

Did the Ogre Magi disappear or is there some mention of it somewhere?

Quote from Foebane >>

Did the Ogre Magi disappear or is there some mention of it somewhere?

Can you maybe provide a little more context? Is that a monster, a species, what?

Ogre Mage also called Oni can be found here

Oni - Monsters - D&D Beyond (Legacy 5E)

Oni - Monsters - D&D Beyond (5.5E)

Yeah oni is the closest they did not make it past 3.5 as a magician variant of the ogre. 

5E The Monster Manual has this lore:

Magical Ogres. Oni are sometimes called ogre mages because of their innate magical ability. Though they are only distantly related to true ogres, they share the ogres' habit of joining forces with other evil creatures. 

5.5E Oni don't have this lore and are no longer Giant but Fiend though, perhaps they wanted to dissociate them further.