A scan of the Antworth word list turns up the following 62 words:
That list leaves out raccoonkeeper.accessibleness accessoriness accommodativeness addressees aggressiveness allottee allottees antiinsurrectionally appellee appellees assessee barrenness bookkeeper bookkeepers bookkeeping cheerlessness classlessness committees commonness effortlessness footlessness greenness heedlessness heelless immunosuppressant immunosuppressants immunosuppressive keelless keenness masslessness mississippians needlessness noncommittally nonpossessiveness nonsuccessiveness oppressiveness pennilessness possessiveness prepossessingness rottenness sleeplessness soddenness soullessness speechlessness stubbornness subcommittee subcommittees successfully suddenness sullenness tennesseeans toolless uncommonness unnecessariness unneedfully unsuccessfully unsuccessfulness wheelless whippoorwill whippoorwills woodenness woolliness