Yep.Maybe Dr. Strange's Orb of Agamotto could be one of the stones...
...or, if it has to start with an "H", the next stone could be a Hoary Host of Hoggoth!
I'm not sure, but wasn't the Eye and Orb of Agamotto shown briefly in Odin's treasure room in Thor?
Maybe not, but those things resembled them. The Gauntlet also seemed to be shown, as well.
http://marvelcinematicuniverse.wikia.com/wiki/Odin%27s_Vault
Although since they are not named on-screen, future MCU producers could probably ignore them if they wanted to. After all, Joss Whedon decided that there were 2 Infinity Gauntlets in the MCU when he did the mid-credits scene of Avengers: Age of Ultron.
http://comicbook.com/2015/05/01/two-different-infinity-guantlets-exist-in-the-marvel-cinematic-u/
I've wondered if maybe the MCU will bring Surtur's sword Twilight for Thor: Ragnarok. The Eternal Flame may be in the Vault, but it would make sense to me that the MCU version of Twilight would be powered by an Infinity Stone. Perhaps Surtur will steal the Aether from the Collector to complete his universe-ending blade.
Eh, I'd like to let some Thor-related stuff stay just that. Not everything has to revolve around the Infinity Stones.