Extraneous rhymes with:
contemporaneous, miscellaneous, percutaneous, simultaneous, spontaneous, acrimonious, aeneas, aerolineas, antonius, bournias, contemporaneous, cyrenius, erroneous, felonious, fresenius, harmonious, homogeneous, igneous, ignominious, instantaneous, miscellaneous, morphonios, palonius, parsimonious, percutaneous, phineas, plinius, sanctimonious, simultaneous, spontaneous, thelonius, unceremonious, vilnius
Extraneous sounds like:
eastern's, estrange, exothermic, extremes, extrinsic