Ebay has lots of things .... your local jeweler may have some as well .
You may also want to check local/regional auction houses for specific 'vintages' of jewelry items as well .
*****and PLEASE , don't forget to check your local antique shops !
I've been seeing a fair amount of jewelry up for sale from private parties too , as of late .
Please be aware that some , if not most , high quality antique jewelry can be higher priced than new stuff , even when the quality of the diamond cut/clairity/carat/color is lacking .
I'd suggest setting a budget BEFORE you go shopping ( but that's just me ) , and take your time looking around - unless you can't resist buying a piece you see .
If you can't find what you're looking for , specifically , you might consider placing an ad for exactly what you're looking for ?
Happy hunting , kevinnov09 !