What two gold figures stood on the ends of the ark's mercy seat?

Answer: Two cherubim

Two cherubim of hammered gold stood at the ends of the mercy seat, facing each other with wings spread upward.

“Make two cherubim of hammered gold at the ends of the mercy seat, one cherub on one end and one on the other, all made from one piece of gold. And the cherubim are to have wings that spread upward, overshadowing the mercy seat. The cherubim are to face each other, looking toward the mercy seat.”— Exodus 25:18-20 (BSB)