The ones most needing back-up are those of the removed models, as Mia Sun and Lindsey Olsen.
Some you cannot own since they were gone before you joined.
Go to your collection and click on year 1999 or year 2000.
Make sure no other year is selected and make sure no filter or search is used.
Here, you should see every card you own that has been removed.
Examples of cards and how to find them on your computer:
These are
e1015 (Hilary C) and
f0913 (Alissa Foxy).
On your computer, in the models folder, you will find these cards by looking at the letter and the numbers.
Manually search for a name starting e (or f), then find
e1015 (or f0913).
note: be aware that there are acdef cards, but the above only mentions e and f.
The a and c cards are older and ended late 2014, when the e and f cards began.
The d cards are really old classic cards originally from a long dead website.
note: the above examples are cards that are still in the store.
I show these so you can find them easily, and you own these cards.
the cards removed cannot be linked here, such as the above ones, so I substituted other cards.
note: every card starts with a letter a-f, and has four numerals following, with prefixed zeros where applicable.
Make sure to know which card collection (letter) before looking, because two or more cards can have the exact same number sequence.
The f (and c) cards are explicit; the e (and a) cards not.