If you've opened the cards that you're looking for, then congratulations
Like most Magic: The Gathering cards, the value of Crystalline Giant depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Ikoria: Lair of Behemoths)
Colossal Whale Colossal Whale beats out other big creatures with islandwalk thanks to its ability to clear up some of the field for you
Then Ill list some cards that might be a bit more expensive but are nice upgrades to your strategy if youre having a good time with the deck and want to invest more into it
Pros Guaranteed threat which plays well in attrition strategy Additional utility from card types for Tarmogoyf Deckbuilding constraint rewards preexisting mana utilization strategy Extra information from Bauble can be utilized in midrange decks Cons Individual card power is lower (no Liliana or Bloodbraid) More vulnerable to graveyard hate Additional mana reduces recursion utility Engine card now more vulnerable to disruption Obosh is Unaffected On the opposite side, I don't think Ponza will really notice Obosh, the Preypiercer getting worse
Its a complex game with complex mechanics and an outstanding number of cards to choose from, so its highly possible that there are undiscovered combos wading in your card pool