I think an important thing we need to take into account now (during the design of Virtual Set #1) is "which" formats these virtual cards will be allowed.
Identifying this (yes, taking a few moments to form a plan) will make this easier, and less confusing, as we go forward.
In summary, I think we should organize it something like this.
[The "theme" of Sets 1-3 is just "forgotten cards"]
Virtual Set #1 would be virtual versions of Fellowship block cards. (Allowed in FOTR, TS, and Movie)
Virtual Set #2 would be virtual versions of Towers block cards. (Allowed in TS and Movie)
Virtual Set #3 would be virtual versions of King block cards. (Allowed in Movie)
This way it will be easier to keep track of which V-cards to allow in a particular format (you avoid mashing of bunch of unrelated things into a single V-set), and it also helps define which mechanics, etc. to allow within a V-set.
I go into detail about it
here.