It depends what you mean by commercially interesting. There’s loads of interest in aerospace (for high temp corrosion resistant structural components) and catalysis but these alloys are pretty much across the board at a relatively low level of technical readiness. It’s developed enough that there’s significant industry R&D and not just academic and government research, but I don’t think there’s really wide-scale deployment yet of alloys with 4+ principal elements

Most high-entropy alloys contain expensive metals so the primary domain of interest has mostly been as a coating for other metals. Recently there has been some work on AlCrMnFeNi, which is the cheapest composition I've seen by far.