Patient Gamers

More than a trilogy, but I've been enjoying Yakuza quite a bit.

I played them in alternating order of release

I don’t mean this in a rude way, but what are you?

As for your question, here are a few options (not all trilogies): Mass Effect Dragon Age Stalker Deus Ex Amnesia Dead Space (skip 3) Dishonored Far Cry 3-6 Metro Saints Row Wolfenstein

For games that you can download and play right away on the Steam Deck

-Mass Effect Legendary Edition Remastered

-Dead Space

-Yakuza series

-Uncharted Trilogy

-Shadows of Mordor and Shadows of War

I would also recommend Max Payne 1-3, but that I know of the first one, at least, does need a bit finagling.

Also the Borderlands series, not sure if it can be played on Deck as is. 2 is a masterpiece though

I also would also not recommend anything Ubisoft right now with the whole deleting people's profiles and game libraries right now, even though Black Flag is one of my favorites. With all the other games and series everyone else is recommending, anything Ubisoft made can take a backseat for now imo.

I was going to recommend you the Uncharted trilogy, but then I noticed you said on Steam Deck, then I proceed to be sad because I don't have one lol.

Is emulating an option? That opens up more stuff!

Ace Attorney Trilogy. I was immediately hooked even though I am not a fan of visual novel or detective games.

Without a doubt, Max Payne 1, 2 and 3

Heya, i may be a bit late to the party (as I am with my games, lol) but I can highly recommend the Gears of War Franchise. If you’re into action games with interesting characters and we’ll balanced gameplay, this is perfect for you. Awesome pacing between action and story. I’ve binged through 1-4 in a few weeks. Now I’m a bit stuck on 5 because of that one Boss fight, but so far the series is amazing imo

Half-Life 1, 2 and 3. You may have to wait a bit for that last one.

Prince of Persia trilogy could work. It's more linear than assassin's creed so it could offer a change of pace.

Dark Souls 1-3 is a perfect casual experience

Elder Scrolls: first complete Daggerfall, then Morrowind, Oblivion, and Skyrim.

As others have said I would 100% recommended the Mass Effect trilogy.

I Also really enjoyed the crysis trilogy, it's like playing through a Michael Bay alien movie. The 2nd and 3rd games especially.

I'd also recommend the Arkham and Witcher trilogies. For the Witcher trilogy I'd wait till the remake of the first game comes out if you plan on playing them in order, as the first game hasn't aged particularly well.