By far, my favorite plant in an angelfish tank is the amazon plant.
Amazon plants come in several colors. My angelfish prefer the red leaves over the green ones - meaning they will lay eggs on a red-leafed plant much faster and more often than one with green leaves.
The color can also be eye-popping. This is a new plant I just placed in one of my community tanks. The tank is about two feet tall so this plant is a pretty large one. (Each of the angels shown are 8-10 inches tall.) I chose to place this one in the middle of the tank as a visual barrier between two pair of angels.
When I approached the tank to take this picture, they thought I was there to feed them, so three of the four angels moved toward the center of the tank to watch me. This is one reason I love angelfish - they are very aware of what goes on outside their tank and will often follow me or the dogs from one end of the tank to the other.