Honestly a lot of PS3/360 games still look fine when emulated so they're not sub-720p. The biggest issue that generation was very poor image quality and frequent drops below 30fps. When they're not blurry and stuttering messes they hold up well enough.

Final Fantasy XIII for having actual colors

Alot of PS3/Xb360 games still look perfectly fine for me, today.
I think they aged better visually than the Wii games did.

I'd have to play them again to make sure, but here's some educated guesses (including some I've played relatively recently, so not all of them are really guesses):

• BlazBlue games
• Final Fantasy XIII
• Flower (not the most impressive game, but has probably aged very gracefully)
• Gran Turismo 6 (not as impressive as more recent driving games, but it seems to have aged quite well)
• LittleBigPlanet
• Journey
• Mirror's Edge
• Ratchet & Clank games
• Rayman Origins (and probably Legends, but I haven't played it yet)

For its visual design, I would also like to mention a PC game: Titan Quest. That game is still very pleasant to look at. Grim Dawn is essentially the spiritual successor to Titan Quest, but nothing beats the colourful visuals of Titan Quest. I'd still rather play Grim Dawn, and it does look good in its own right, but Titan Quest is just so much more pleasant to the eye.

I'm going to refrain from mentioning other PC games, because many of them have probably held up quite well.

Already did that:
https://gamrconnect.vgchartz.com/thread/250377/which-3d-6th-gen-games-have-aged-the-most-gracefully-visually-in-your-view-and-why/

I actually think games like Mario Galaxy 1/2, Sonic Colours, or Red Steel 2 look just fine with a good set of component cables.

Ratchet and Clank
Mirror's Edge
Bioshock Infinite
Journey
Portal 2
Halo 4

Bit of a cheat, but Ni no Kuni as well

Skyward Sword. Beautiful game.

Any still frame from that game looks like a painting. Close ups are not as impressive as scenery further away. But it is a unique colorful style. 

Ran via emulator in high resolution? Absolutely.

Original Wii, either on CRT (better option) or HDTV (terrible option)? Still beautiful, easily contender for best art style in that gen, but it really suffered from that 480p presentation.

A lot of PS3 games, particularly after year 3 or so, aged quite well. In terms of which games in particular, from the ones I played FF13, Uncharted series and gran turismo stood out for me. GTA5 for its scope, the fact that it's a PS3 game, is quite outstanding to me

From the Wii I'll say the galaxy games were beautiful and still look good today. Shout out to Mad World which i thought looked cool at the time, and sonic colors too which looked quite good