I ended up with the statue(?) that lets you entomb the lowest cost card from the pyramid and BOTH amulets that let you repeat actions. So, I got to the point where I was entombing 4 cards in 1 turn.
It's not a statue, it's the "Book of the Dead". It has a high cost (8) but even with that I wonder if it's a little overpowered.
We've just finished a game where I pulled off exactly the same strategy as described in the quote; BotD and two Tyet Amulets (this is the action repeating amulet seen here ). It proved unstoppable.
In the previous game the winner managed to get both BoTD cards and similarly won the game by a large margin entombing 3 cards a turn and hastening the end of the game while simultaneously extending his lead.
The reason I wonder if BotD is overpowered is that it combines the ability to buy a card (even the expensive phase III cards) while simultaneously entombing it all with a single card. Normally you would need multiple cards to even do one of those things, especially later in the game. The cost and the fact that is has to be the lowest cost card on the pyramid you buy/entomb are some down sides but they don't feel like they've balanced the card to me. I can't see a strategy where BotD wouldn't be useful and when it's duplicated it's hard to beat.
Now ok, I've been here before, sometimes when you're early on in learning a game you hit on the first (usually most obvious) killer strategy and it seems unstoppable until someone else figures another and then balance returns to the game. What are the other power cards or power combo's out there to balance out this game?