UPDATE:
I found this issue explaining the relicensing of rust game engine Bevy to MIT + Apache 2.0 dual. Tldr: A lot of rust projects are MIT/Apache 2.0 so using those licenses is good for interoperability and upstreaming. MIT is known and trusted and had great success in projects like Godot.
ORIGINAL POST:
RedoxOS, uutils, zoxide, eza, ripgrep, fd, iced, orbtk,...
It really stands out considering that in FOSS software the GPL or at least the LGPL for toolkits is the most popular license
Most of the programs I listed are replacements for stuff we have in the Linux ecosystem, which are all licensed under the (L)GPL:
uutils, zoxide, eza, ripgrep, fd -> GNU coreutils (GPL)
iced, orbtk -> GTK, QT (LGPL)
RedoxOS -> Linux kernel, most desktop environments like GNOME, KDE etc. all licensed GPL as much as possible
Most of the rust projects I listed are replacements for stuff in the Linux ecosystem which are licensed (L)GPL. The most popular toolkits by far are GTK and QT, both LGPL