Some models have come back for return visits (e.g. most of those who have more than 6 cards - there are usually six cards per shoot - in fact I think Eufrat has already done 2 shoots, with 6 then 3 cards), so it isn't out of the question that some of the earlier models may return and do some more.
Also, some older cards that weren't released at the time for one reason or another, are released from time to time.
Always worth remembering that the oldest VGHD cards were shot in 2007 though, so quite a few of the girls from back then, or even some time after, have retired from the business now.
Blue Angel is still in the business, and is among the more popular adult models around, so a return visit from her is possible. Whether she would come back to make another set now, is anybodies guess though. Probably depends on the money on offer and how convenient it would be in terms of her schedule.
Then again look at Jana Cova. She did a set of 6 cards for VG a few years ago, then decided to come back and make some more as her very last job before she retired.