Ottilia

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://sursassiala.ch/2015/01/15/familienforschung/
Https://nossaistorgia.ch/entries/m3zVp9rGD8d
Https://nossaistorgia.ch/entries/lqYVyBbDeAG
Https://www.portraitarchiv.ch/portrait?page=57
Http://www.annalas.ch/persunas/display/q:Ottilia

Also Banatswabian: https://ofb.genealogy.net/famreport.php?ofb=zichydorf&ID=I32059&nachname=Brachth%C3%A4user&modus=&lang=de
https://ofb.genealogy.net/famreport.php?ofb=zichydorf&ID=I24820&nachname=Gr%C3%A4bldinger&modus=&lang=de

This name was also used among the German minority in Bessarabia (and by far more common than Ottilie): https://ofb.genealogy.net/famreport.php?ofb=krasna&ID=I12007&nachname=Klug&modus=&lang=de

Also Hungarian: https://hu.wikipedia.org/wiki/Ot%C3%ADlia -- mentions Ottilia
http://www.nytud.hu/oszt/nyelvmuvelo/utonevek/osszesnoi.pdf
You'll find numerous bearers on social media.

Also a German variant of Ottilie: https://de.wikipedia.org/wiki/Ottilia.

Also used in Sweden. [noted -ed]