I only have three, but
1. Flying. I was actually very good at it for a first timer. I was flying around Superman style, and was actually flying so fast at one point (picture the scene from the Matrix where Neo is racing to save Trinity while she is falling) that the dream began to fade around me. I slowed down to recover it.
2. Exploring mirrors in detail, including studying my reflection and crossing to the other side.
3. Changing the appearance of my own dream body.