@paulasadoorian

@steamdeckhq just posted an article about the most played games on #SteamDeck that could be informative.
Valve Releases List of Best Steam Deck Games of 2023

That said, it does really well for slightly older games and tons of indies that are in early access and not yet certified.
Check out the ProtonDB website to see what games that might not be certified actually work just fine.

I'd personally recommend
#VampireSurvivors, #SoulstoneSurvivors, #Brotato. Just about every game in the survivor / bullet heaven genre plays fine since the controls are normally so simple.
#DeadCells, #RogueLegacy2, #TrinityFusion. There are tons of these metroidvania-rogueli[tk]e games that work great.
#BaldursGate3 has a wonky controller interface, but that hasn't stopped me from putting in over 200 hours on my deck. The #DivnityOriginalSinEnhancedEdition interface is much better even though it's the same developer. #DivinityOriginalSin2 works well, too.
If you like #ARPG games, I've played a few such as #GrimDawn (which works but does not have official support), #VictorVran. I tried #DungeonSiegeIII which was a disaster (it also didn't play well on the deck).
#ElderScrollsOnline works surprisingly well once you get it fully installed and configured. It's the only MMO I can play on my deck.
I put about 20 hours into #Tyranny when I first bought my deck in late 2022.

Edit:
#Warframe should be another MMO that works on the deck, but I haven't played it in a few years so I haven't tried.

@corbden
I bought the $650 #SteamDeck in March of 2022 which means I got it in October. I worried the whole time I was waiting that I'd made a mistake. That I would hate it. That it would be uncomfortable or too heavy.
I wasn't sure I'd even go through with the purchase when I got the email that it was time.
But I did.

I love it. The biggest limitation is the battery life, but if you are playing in bed, you'd be able to have it plugged in.

It's bigger than you think if you haven't seen one in person. It looks too big, but once you wrap your hands around it, it feels perfectly designed.
I have no problems using both analog thumbstick, the XYAB buttons, both touchpads, the top buttons, or the triggers. The back paddles, back buttons are a little finicky, but you can sort of squeeze them by closing your fingers in and that works. It's easier than pushing the buttons, too. Also, the D-Pad is little awkward for me to use. Finally, the touchscreen itself is difficult to use because you really need both hands to hold the #SteamDeck
You can use the touchpads to access the on-screen keyboard, similar to how it worked with the old #SteamController. So you don't have to touch the screen to type, but it is faster if you do. Wiggling the pointer around to the letters you want and gently depressing the touchpad to type it is difficult to do quickly.

Game-wise, it's wonderful. I've put at least 150 hours of gaming into it, most from my recliner, since I got it.
I've done minimal fiddling with the settings. The only settings I changed permanently was limiting the FPS instead of 60. That saves some battery without making games look terrible.

I do not regret purchasing it. My thumbs regret it. I'm getting Nintendo thumb like I had as a kid, but it's worth it.
I'm not sure what kind of games you like, but I have played Roguelites, Medtroidvania, ARPGs, and RPGs without issue. It can run FPSes but I get motion sick.

In my experience, these are great on #SteamDeck which means no complications and controls are fully integrated:
#RogueLegacy2
#RogueLegacy
#Hades
#DivinityOriginalSinEnhancedEdition
#DivinityOriginalSin2
#VampireSurvivors
#DeadCells
#VictorVran

I want to talk about #VampireSurvivors for a second. I have that game on PC / #SteamDeck, but there is also a mobile version. I've tried playing the mobile version on my tablet and it was awful. It was unplayable for me because the touch controls were so soft. But on the #SteamDeck, it is fantastic. I am able to deftly weave around enemies in a way that was impossible on the tablet.

Here are games that worked fine for me but weren't fully integrated, so prompts for keyboard or having to rely on touchpad and triggers instead of keyboard and mouse:
#Tyranny
#GrimDawn
#FaerieSolitaire
#DiscoElysium
#ReturnOfTheObraDinn
#SlayTheSpire
#ShadowRun

#CryptOfTheNecrodancer is "meh" just because it's better with the D-pad and that is hard for me to comfortably use.

There are some other puzzle games and adventure games that were fine to play, but you are using the thumpad as a mouse and the triggers as mouse buttons. It takes a little bit of getting used to.

I have terrible nearsightedness. I hold the #SteamDeck about 4" from my face to play it, which has the side effect of making the screen seem to be absolutely gigantic.