Little is known about the
giants of Draenor, other than the fact that they lived on the world of Draenor. They also had two eyes, and its skeleton is human-like but very big (Warcraft II, Warcraft III, World of Warcraft).
In Warlords of Draenor Edit This section concerns content exclusive to Warlords of Draenor.
BlizzCon 2013, indicated that the giants of draenor may have been related to gronn and ogres. From concept art, these giants may be really big gronn.
Temple of the Damned Edit
This section concerns content exclusive to Warcraft II.
Warcraft II, the Temple of the Damned structure was said to be constructed from the bones of these giants.  ( W2man 84) These structures would later be used by the Scourge and Forsaken in the Undercity.
In Warcraft RPG Edit This section concerns content exclusive to the Warcraft RPG, and thus unlikely to be canon.
says that the ogres are one of the last races of Draenor's giants, implying that there has been more than one race of giants that have lived on Draenor. Horde Player's Guide  ( HPG 156)
This article or section includes speculation, observations or opinions possibly supported by lore or by Blizzard officials. It should not be taken as representing official lore.
These creatures may very well be related to the
gronn, the lords of the ogre race, and perhaps all races of Draenor's giants may be related distantly. They are referred to as "Grom" in Orcish.