Torchlight II, Dungeons and dragons, Last Chaos, WoW, Anarchy Online, Most Muds that still exist... Zelda, Rage?, The Sims III, Spore, Crysis, Prototype, Alice in wonderland...
Not sure what you believe "competition" is...
Similar depth? Similar structure? Similar graphics? Similar sort-of-statistics? Similar fights? Same price-range? Direct copy, but not the actual game content?
I think any game that has the following would qualify:
1. HUGE open world that you can fully explore from the beginning of the game or within the first few levels.
2. You can "interact" with almost anything within the world. This means you can grab anything (loot), talk to anybody, attack anybody, etc.
3. It has to be an RPG or something close to the definition of RPG. Basically it has a combination of some of these things: skills/attributes/perks, inventory/loot, spells/abilities, quests, etc.
Some games like RDR are somehow close to the definition but not 100%. RDR has a big open world that you can explore from the start. It also has quests, loot, etc. However, the game is somehow limited with regards to "interaction". Loot is limited and you can only talk to certain key characters. It is also pretty limited with regards to character development. Also, although RDR's is a big game, it is not in the same level as a bethesda game (at least that's my opinion).