Material science and manufacturing are two that have always seemed interesting to me, particularly monocrystalline stuff like semiconductors, optics, and metallurgy.
Varda uses the low gravity environment of space to create medicines that work better than when they're made on Earth.
Don't think Varda (or anyone else) has ever sold any space produced drug? It's all very much experimental small scale. Realistically, something has to be super potent and super expensive to even consider it (that rules out anything mainstream).
Not that anything is really produced in space either, more like passively transformed into some crystal form from a liquid state or whatever. Environmental assistance more than anything else.