By far, my favorite plant in an angelfish tank is the amazon plant.
The amazon plant grows in the angelfish's natural habitat. Its broad leaves are perfect for laying eggs and when the young hatch, they are often moved from one leaf to another. When they begin to swim, the leaves provide some protection from predators.
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.