I use Hyrpland, and so there are times where I need to use GTK or Qt tools. I generally don't like KDE-based tools though because they are dependency-heavy.
2.1.0 brings us Wayland? Very exciting! Definitely will check it out (as a full session), as I always pick apps from either XFCE or LXQT for my tiling window manager set up. I've been using Thunar lately, though I'm open to switching back to pcmanfm if I want to.