You are unlikely ever to see another Rover Ro-Set, Italian
Not quite a button filler, and not taken today, but I ran across it in old files, a truly great pen from Germany, a Rakete.
Minerva, OMAS sub-brand
Picking up on Pentrace's Sunday topic of button fillers
Soennecken Präsident 1 and a mystery pen
WTF, a Juska? German