Marbles has a quantizer yes, with 6 scales built in and the ability to set your own if you choose. You can set the degree to which the notes are chosen, ie on the installed major scale you can tell it to lean towards octaves, fifths, thirds, or filling in all the notes, and then into semitones.
It’s very flexible and could be just want you want… It’s just not a sequencer on its own. But it can produce pleasing melodies that you can have a fair amount of influence over.