Slint yes but it’s commercial. Iced didn’t have a real accessibility story when I looked a few months ago. Ditto for egui. Also egui is immediate mode only which limits its general applicability.
It's not actually about paying money or not, I've signed up for many a patreon or what not to support open source projects I use. I fully believe in paying people for software. But for core things like this I do prefer MIT/APACHE.