What I mean is: keyboard only or a sane combination of keyboard plus trackpad. For the other stuff I have a desktop thank you very much, but I don't even have space for a mouse where I usually use my laptop.

Obviously, they have to have an OS X version.

Also, by "modern" i mean done in the last 5-10 years, not packaged DOS stuff (I have most of those anyway).

Any suggestions welcome, thank you.

Definitelly Freedom Planet and Valdis Story. As far as I remember, also in Steamworld Dig and UnEpic you don't need anything else but keyboard (not sure about the last one though, I have played in it long time ago) - and both are great as well (although some people are complaining about monotony in Steamworld Dig).

I've played a couple of years ago in Rayman Origins - really nice game, plays perfectly on keyboard only (OS X version is not available on GOG though).

Gods, i think I'll just give up.
I bought UnEpic and it seems fine... except everything is too -ing small on the 13" screen!
Obviously whoever developed it had a 27" and never tested on anything else...

Ouch, not good. Although I've played in UnEpic on device with 10,1' screen in the past and I personally didn't feel that everything is too small (but I'm guessing that every player has different "margin of tollerance" for such things as monitor and size of stuff on screen). Maybe try with some low resolution (if it's available, such as 800x600).

Anyway - in that case I think that games with big character/enemy sprites would work better. I've played in Freedom Planet and Valdis story on my GPD Win (with 5,5 inch screen) and it was really great (both games have quite big sprites and it should work better - I would recommend here to try Freedom Planet's demo, but unfortunately, it is available only for windows).

Shovel Knight should work. While the game supports (and is designed for) gamepads, the controls are simple enough that a keyboard should work fine.

I would avoid Guacamelee, as while the game is technically playable with a keyboard, it requires fancy button combos that require pressing multiple keys at once, and some keyboards don't handle that well, and even for those that do, it is still not ideal to use a keyboard for that game.