Used denim from pants, skirts, shirts, etc., isn’t the most likely medium for art, but Korean artist Choi So Young can see whole urban landscapes in it. He (or she, websites differ) is especially clever in using the bits most textile artists don’t use – the belt loops, pockets, seams, pocket liners, labels, and buttons. The pieces are best described as collages. I believe acrylic paint is also used.
Other work by her/him is at artnet. So far my searches haven’t found any biographical data, except for year of birth (1980,) education, and residence (Korea.) I’d love to see a video of the artist at work, but while my YouTube search found some bizarre stuff, it turned up no artists.
Ian Berry is another artist who works with denim, often in portraits. I wrote about his work here.