Richarson rhymes with:
ingimarson, arson, barson, carson, clairson, corson, coursen, courson, duerson, farquharson, farson, forson, frierson, garson, grierson, gunnarson, halvorsen, ingimarson, karson, korson, lairson, larsen, larson, larsson, laursen, lorson, luerssen, marson, mccarson, morson, myerson, norcen, orson, oscarson, parson, pearson, peerson, pehrson, peirson, pierson, rierson, ryerson, schneerson, scorsone, shearson, thorsen, thorson
Richarson sounds like:
regression, richerson, rickerson, rogerson