Bethesda has been using the Gamebryo/Creation Engine for their RPGs (Fallout/Skyrim). I think Bethesda has only used idTech for Rage/Doom.

The Wolfenstein games and The Evil Within are both idTech as well.

They are too many to name. Check this[1] page for each gen. From gen 2 onwards, you'll be astounded.

[1]https://en.m.wikipedia.org/wiki/List_of_Unreal_Engine_games

Look at the top-selling Xbox One games:

http://www.vgchartz.com/platform/68/xbox-one/

You have to go down to #31 to find an Unreal Engine game (Batman: Arkham Knight). The only licensed engine game that I know of in the top 30 is Titanfall, which licensed the Source engine from Valve. The situation is similar for the PS4.

#9 Gears of War: Ultimate Edition uses UE FYI

So, this is correct and I thank you for the correction. Having said that, I don't think that changes my point much if any -- there's one game in the top 30 sellers that uses Unreal Engine, and it didn't use it as a third-party engine -- Epic developed both UE and Gears of War.

By and large, the developers of AAA games don't license an engine from a third party.

Bethesda's subsidiary id uses idTech. Bethesda Game Studios (Elder Scrolls, Fallout) has used their Gamebryo/Creation engine for about 15 years.

So, as I've noted above, other studios besides id use idTech at Bethesda -- you could argue that MachineGames doing the Wolfenstein games is still an id property, but Tango used it for The Evil Within, too. And I did say "or something geared for their RPGs." I couldn't remember the name Creation Engine when I was posting on my phone at a Christmas gathering.

MachineGames and Tango are owned by ZeniMax[0], the Bethesda parent company. I faintly remember someone (Carmack, maybe?) mentioning that idTech5 would only be licensed to studios within ZeniMax.[1] Of course, anyone can use idTech up to 4, since those are open source, and were licensed out.

[0] https://www.zenimax.com/studios

[1] http://www.gamasutra.com/view/news/29886/id_Tech_5_Rage_Engi...

Yes, MachineGames and Tango are owned by ZeniMax. They are published by Bethesda Softworks, the parent company of Bethesda Game Studios and a ZeniMax subsidiary. I don't really understand the point of this faux pedantry, seeing as there is a meaning of Bethesda that fits my post.