Any good free, open source UWP Windows apps?

Looking to replace most of the Microsoft garbage with functional, native, good-looking apps.

Already using FluentWeather, FluentCast, Screenbox, Wino Mail, Unigram, AniMoe (Anilist client)...

Wanted Windows to ID Fluetro PDF as a PDF app, but for some reason that isn't happening...

Any other suggestions are also welcome...