Just take the 22,630 total unique cards in Gatherer, and multiply that by the number of different printings per card, like the 10 versions of Remove Soul. That gets you to a total of roughly 49,998 total unique printings
Playtesting is a crucial part of refining your deck
Some, like Candelabra of Tawnos, The Abyss and Eureka, are already extremely expensive and probably not worth buying unless you really, really want to play High Tide
Bhaal will naturally gain indestructible as the game goes on and your life total drops, which is great, but the real power comes from its second ability
You get to put a +1/+1 counter on Sab-Sunen during your first main phase, then draw two cards if she has an odd number of counters
Birthing Pod's ability is quite powerful in any context, but when a deck is specifically built to take advantage, it becomes nearly impossible to beat