Toivonen rhymes with:
karvonen, callanan, clendenen, feminine, hallanan, heinonen, hemocyanin, hiltunen, juntunen, karvonen, keranen, korhonen, latenan, lebanon, leinonen, leppanen, melanin, moilanen, niskanen, raisanen, vanwagenen, veegenan, waisanen, wirtanen
Toivonen sounds like:
t-bone, tabone, tappan, tappen, tappin, taubman, tavano, tebben, theophania, tiffany, tiffin, tippen, tippin, toben, tobin, toibin, toobin, topham, toppin, toupin, towbin, tubman, tufano, typhoon