Artur

Also Romansh:
Source: "Vornamen in der Schweiz. Prénoms en Suisse. I nomi in Svizzera. Prenoms in Svizra" (1993) published by the Association of Swiss registrars
https://nossaistorgia.ch/entries/zmkMAA12MrN
https://nossaistorgia.ch/entries/w4LMYvrZ2lW

Also Albanian: https://instatemra.shinyapps.io/emra/
https://sq.wikipedia.org/w/index.php?search=Artur&title=Speciale%3AK%C3%ABrko&go=Shko&ns0=1 [noted -ed]

Also Picard: https://pcd.wikipedia.org/wiki/Ro%C3%A9_Artur
https://pcd.wikipedia.org/wiki/L%C3%A9ginde_Artur_ech_Ro%C3%A9

Also Provençal: https://ieo-oc.org/spip.php?page=article&id_article=290 --- Source: Institut d'Estudis Occitans

Also Croatian: https://actacroatica.com/en/name/Artur/

Also Romanian and Moldovan: https://ro.wikipedia.org/wiki/Artur_Ioni%C8%9B%C4%83
https://ro.wikipedia.org/wiki/Artur_Silvestri
https://ro.wikipedia.org/wiki/Artur_P%C4%83tra%C8%99

Also Kashubian: https://csb.wikipedia.org/wiki/11_g%C3%B2dnika

This name also exists in Armenia. [noted -ed]

Also Manx: http://www.ceantar.org/Dicts/Manx/mx01.html
http://www.isle-of-man.com/manxnotebook/famhist/fnames/kpn.htm
https://en.wiktionary.org/wiki/Artur#Manx

Also Belarusian, spelled Артур. You'll find numerous bearers on social media. [noted -ed]

Also used in Norway. [noted -ed]

Artur is also used in Croatia.

Also used in Romania. [noted -ed]