- 10 cards from base set are always familiar
For the default 10, I'd use the "first game" set of 10!
Cellar, Market, Merchant, Militia, Mine, Moat, Remodel, Smithy, Village, Workshop
Although I think I would go up to 12, add the other two pure vanilla main set cards - Laboratory, Festival. Just, slightly more variety for your 2nd game if you don't go click on that tab. Maybe even a couple more, I dunno.
I would not have Landmarks randomly show up until the player is "familiar" with at least one kingdom card from Empires. Ditto Events unless they are "familiar" with at least one card from Adventures or Empires. Just, these extra-weird things, let's keep them from appearing right away.