I count 220 examples in the Scrabble dictionary ospd.txt. Of course, many are uncommon. Some of the highlights:
beery - berry boobies - bobbies boogy - boggy boos - boss cheery - cherry coolies - collies coopers - coppers drool - droll drooped - dropped feel - fell heel - hell hooter - hotter kneel - knell looped - lopped marquees - marquess peeper - pepper pools - polls pooping - popping purred - pureed referred - refereed rooted - rotted snooty - snotty steeped - stepped stooped - stopped tools - tolls tooters - totters trees - tress weeded - wedded whooping - whopping
Department of Mathematics
http://www.math.ubc.ca/~israel University of British Columbia Vancouver, BC, Canada V6T 1Z2