Unidentified decoration studio/souvenirware producer. Just a guess, but the written form "A.O.Fi" may indicate a name like "A.O. Fischer" or something similar. Specalized in touched-up transfers as well as etched gold decorations. Mainly (re)decorated collector cup trios ("Sammeltassen") as well as tea/coffee sets but also worked on a few beer steins, vases and thimbles.
Earliest ID per original mark Hutschenreuther Kunstabteilung (1968/1969), newest ID found on unmarked deco plate, front stating Wandertag 1982 Festspielhaus Bayreuth. Next to other producers this mark can be found on items made by Porzellanfabrik Arzberg (Arzberg), Hutschenreuther AG (Selb), Heinrich & Co. (Selb), S.P.M. Walküre (Bayreuth) and Porzellanfabrik Tirschenreuth (Tirschenreuth).