Re: Hello from the San Fernando Valley
Schwinn used that same frame over a couple of decades, maybe longer than that. Motorbike was one... I can't remember. Some were high dollar fancy ones, like the Panther and Motorbike and others were more basic with different paint decals and doodahs. Just look under Schwinn frames and memorize what the straight bar frame looks like. Probably the listing won't say what it is because the seller doesn't know.
Other makes had similar frame designs, but a little different. Elgin, Rollfast, Hiawatha. Colson, Monark, Hawthorne... are some that come to mind. I would just look under vintage bicycle frames and see what strikes you as good looking. If the head-badge is missing then the seller may not know what make it is. You could also look under pre-war bicycle frames. Unless you are settled on a straight bar (Panther) frame, I'd just look to see what strikes me as a good looking frame, similar to the Panther. You'll find something.
Someday when I grow up I will probably lose interest in toys with wheels, but until then...