I actually like the elementaryOS enail client - not sure if it has an actual name
International: Weather&Radar - best overall UK: Wearher Forcast UK or MetOffice app (same source but different UI) GER: Deutscher Wetterdienst und Regen Vorschau (very accurate but only GER)
reeder on the ipad (best ui for me) and vienna on macos (as its open source, themeable and fast)