Are you seeking for complete games only or are demos OK?
I know only a few games that I'd consider Adventure, despite the tags sometimes added to them by the developper.
There's one called
Asylopole, but I don't know if it has been translated into English.
You can also try the demo of
Miraculo Island as it's a blend between a visual novel and an adventure game, with a slight touch of horror, judging by the demo.
Also, not to advertise or anything, but my own demo of
Bleeding Moons is an interactive adventure novel, as I call it myself.