I collect early 20th century American production art pottery, so all that stuff was made by then-common Ohio potteries like Weller (the low one with the brown rim) and Robinson Ransbottom (the midsize green sand jar for cigarette butts) and McCoy, etc.
Mostly I’ve found them in thrift shops and flea markets because they’re not popular with millennials so a lot of pieces are being tossed out as the elderly original owners pass away or downsize.
The animal-shaped pottery flower frogs from the same era that I also collect I mostly find online because they just don’t show up in the wild where I live.