I'm not sure at all why to use Rust for a desktop app unless it's something super complex and demanding like a browser (the motivation for developing Rust in the first place). Otherwise use a garbage collected language that handles more bookkeeping for you.. Also the GUI toolkits so far aren't written in Rust afaik.
Hmm would a GUI toolkit or even a window system (X or Wayland server) in Rust count?
Otherwise I mostly want libraries and CLI programs rather than GUI ones. Or a kernel module. Like rewrite btrfs in Rust since the C version is still full of bugs after all these years from what I can tell.