What are your favorite "more mature" embellis Sewing Machines Parts and Sales in Los Angeles

I am an amateur sewist who works with children. I want to avoid using embellishments like ruffles, ric rac, fabric flowers, which my students are likely to have on their clothing, bags, etc. So far I’m thinking about embellishments like lace, contrasting bias tape, maybe geometric applique? What other embellishments could I use?

Any and all suggestions are appreciated!