It would be nice if Totem add a little flag on all the cards/models that are deleted (or about to be deleted).
I completely agree.
Until a relatively recent update the Release Date filter allowed you to find those cards that had no release date - these being the withdrawn cards (as you will see if you go a withdrawn card's details page. So this gave us an easy way to check which of these cards we owned.
You can still use the filters to find the withdrawn cards, but it's now a complex operation.
1. Enable all the cards in your collection and clear any active filters
2. Tick all of the years in the Release Date filter (this will show you all of your non-withdrwn cards)
3. Disable all of the displayed cards (Use Control-A to select all of them)
4. Clear your filters
5. Tick the Enabled in the Activation filter
I don't regard that as being a practical way to do it, but at least it's possible.
A simpler way to find them is to sort your collection by Release Date (a new option with these recent Beta releases) and choose Ascending order - they will then be displayed before the rest of your collection. You will then have to manually determine just where they end and the non-withdrawn cards start, but that is not difficult.