First group, Post medieval copper alloy coin Spain, Philip IV (1621-65) copper countermarked four-maravedis, 1655 Possibly an earlier issue of Philip III. Lots available on ebay for a few dollars. What I have also seen is folks taking these coins and making them into cufflinks and selling them.
Second group, 17th-18th Spanish bar-style cufflinks. Looks like the makers mark or initial of the owner is worn. But the 3 dots on each side help in dating the piece.