Retro Collection has been discontinued, despite demand for the line, apparently not being found by many collectors at Target, often with the line never showing up at retail at all.
http://www.jeditemplearchives.com/2019-06-01-fact-or-fiction-one-target-employee-claims-retro-collection-discontinued/I don't really care about it personally, because the vintage figures are no more than a curiosity to me when modern figures exist. And I viewed the line as a bad idea during the current state of the toy franchise struggling at retail and struggling for relevancy with no child fans.