Other than that, I use the same kind of applications you'd expect any desktop user to use, from file managers to text editors and from office suites to web browsers. Only most of them are Qt-based :). The only GTK applications I still use are Firefox (GTK-ish) and Emacs, which can still be compiled against GTK2 which is a good enough compromise for me.
It's nothing personal, I don't want to get into a big rant about how Linux used to be about choice and about how Gnome is a Red Hat conspiracy, or whatever flag is being waved in 4chan & friends. I just don't like GTK3's UX choices. Oversized widgets, awkward scrollbars and hamburger menus aren't pleasant to use on a 30" monitor. A few years ago I tried to get around that with a custom theme, but theming is... kind of frowned upon in GTK land, so it didn't end well.
But, you know, their code -- their choice. I don't like the choices but I think it's a big step forward from the '90s and a big test of maturity for the open source community. Making (what I believe to be) our own mistakes is way better than cargo culting Microsoft and Apple, which is what we've done up until 5-6 years ago.
Edit: also, why are you folks downvoting the parent comment? It's a productive question, even if it looks uninformed (i.e. I'm guessing the downvotes are because it's conflating "GTK applications" with "desktop applications", which looks silly but have you had a look at Ubuntu lately?). If you think that's a stupid question, fine, but are you really that sure you've never asked a stupid question in your life?