Hello there, friends!

I'm looking for a game that my mom (67 years old) can enjoy and has simple straight-forward mechanics. Any ideas? :). She doesn't have any preference but she asks me to play whatever I'm playing so I think she will be ok with almost anything!

Hints:
-Easy to play
-Straight-forward gameplay
-basic learning curve
-No complicate lore/story
-simple controls
-Gamepad support

I noticed that she doesn't read or follow the lore but she is easily convinced by the game mechanics. I'll do my research based on your suggestions, Thanks in advance!

That last bit is interesting. What type of games does she enjoy? Any she played all ready?

I'm going to give my 2 cents ahead: Morrowind and Oblivion, the lore is optional and the game play is basic.

Maybe she would like

stardew valley
trine series.
gris
Divinity Original Sin (can be played coop with controllers)

If anything else comes to my mind I will edit my post.

Adventure games. Very basic, search and find, solve puzzles, point and click.

How about The Adventure Pals or Steamworld Dig? They're pretty straightforward and rather easy platformers with gamepad support. Although they do feature occasional talking to advance the story and get access to new levels/areas.

As suggested above, Trine might be a good fit, too. In that series you can completely ignore the story and it doesn't really change a thing.

Thanks, guys, so far we played card games, fighting games, basic indie "jumping" games like Montaro (these i think are her favorites), platforms, etc. She also enjoyed bloodstained but it was a little bit hard

Zuma's Revenge

https://www.youtube.com/watch?v=ExDGZpeeKmU

BASS fits and it's free.

Though I don't know about controller support since it's a P&C.
Also Mortal Kombat actually fits your qualifications.

Knytt, maybe? the first one's plot is almost absent and it has nice simple graphics and is pretty easy to beat. don't know about controller support though. (Knytt Underground does support it but is quite story-heavy and isn't presented here.)

Sadly not on GOG, but a game your mother may enjoy is Plants vs Zombies; my mother loves it and I recommended it to my friends (brother and sister) and now their mother loves the game too, lol. It's very easy to learn and lots of fun, I highly recommend it. :)

Agatha Christie - The ABC Murders

Hidden Object games are easy enough and addicting.

Triple Town. It's a simple merge 3 style game with cute graphics and a simple decoration/ advancement option between games.

maybe into the breach?

When it comes to platformers you can get two of the best platformers on PC right here on GOG.

*) Dust: An Elysian Tale
*) Ori and the Blind Forest: Definitive Edition

Though Ori can get quite hard in some places I'd still recommend it.

Other than these two I can also recommend Stardew Valley, Steamworld Dig, Trine (which are also here on GOG) and the first Plants vs. Zombies (which sadly isn't) which were already mentioned.

Oh, and of course the recently released Spyro Reignited Trilogy, sadly also not here on GOG.

With these games she'll be occupied for a long time.