I’ve always found earing and necklace sets that they enjoy (they don’t have to be expensive) and are fun to wear are always a hit. Its also a good way to test the water with something relatively cheap (>$50- $100) to identify their style. If possible, I would strongly recommend buying in-person at something like a craft market or farmers market: anything in-person. How something looks online often just does not translate to in-person.

The key here is a set, something they can add in-combination to something they already have.