You can use strip sets & still get a pretty random scrappy look. Cut your sets of 3, toss em all in a grocery sack & pull out & sew together randomly, as opposed to a planned xox+oxo+xox nine patch.
Some people go for a true "charm" quilt, which I take to mean no two fabrics repeat, so they are able to say "there are 4,320 different fabrics in this quilt" (90x108 queen sewed with 2" cut squares)