I love looking through the card pool and seeing what cards were available in the very beginning of the game, and what limited strategies they had
As far as I can tell, looking through the bazaar they had:
Up to and including Chaos Seed
Up to and including Plague
Up to and including Otyugh
-Up to and including Shrieker
Up to and Thorn Carpace (not available then)
Up to and Including Rain of Fire
Up to and including Mind Flayer (Artic Squid at times available in the bazaar)
Up to and including Blessing
Up to and including Flying weapon
Up to and including Devonian Dragon
Up to and including Nigtfall
Up to and including Phase Dragon (not immaterial at the time)
However, these are probably very wrong, just assumptions based on reactions of the Flashkit forums. But in general, you can see that the game has come a long way.