Thereby rhymes with:
hereby, nearby, whereby, adl-tabatabai, bae, bi, buy, by, bye, bye-bye, chubais, drive-by, dubai, good-bye, goodbye, hereby, nearby, standby, whereby
Thereby sounds like:
tariff, tarp, tarpey, tarpy, terrify, tervo, tharp, tharpe, therapy, there've, thereof, thorp, thorpe, thorup, thrive, throb, throop, throve, todoroff, toribio, torp, torpey, trabue, trap, trapp, trappe, traub, trib, tribbey, tribby, tribe, trip, tripe, tripi, tripp, trippe, trippie, trivia, troop, tropea, trophy, tropp, troubh, troup, troupe, trove, trubey, truby, true-view, trupp, tryba, turbo, turf, turvey, turvy