Outdoor or indoor pond? Larger Sunfish (Warmouth, pumpkinseed, longears), You could also add some rock bass. A school of yellow perch is a beautiful sight, depending on your geographic location (they like cooler temps than most). I would stay away from Large mouth/small mouth bass as it will limit what other fish you can put in.
I am actually in the process of building a 1250 gallon indoor pond in my basement, with a glass viewing window. Enjoy the build and let us know how it turns out. Good Luck!