Unmarked rhymes with:
marked, remarked, unremarked, barked, embarked, marked, parked, remarked, sparked, unremarked
Unmarked sounds like:
unhorsed, unrehearsed, unrequited, unrest
marked, remarked, unremarked, barked, embarked, marked, parked, remarked, sparked, unremarked
unhorsed, unrehearsed, unrequited, unrest