Becoming "your own" domain registrar without having to deal with ICANN was another interesting one to me (after checking into how all those .eth domains popped up).

It was exciting when I first looked at it and then I realized that this was actually not "democratizing" anything so much as ensuring a new class of folks would be able to create new centralized "everythings" in a new environment outside of the current system - without the benefit of the years of testing, regulation, and (sure) cruft that our current systems have because they're subject to political forces (which is actually a feature).

Maybe starting the wild west over again is a good thing? My money's on "not really" at the moment.

Becoming a market maker, liquidity pools, yield farming, flash loans (short term borrowing of lots of money)