Soundly rhymes with:
profoundly, roundly, bindley, blandly, blindly, brindley, chandley, fendley, findlay, findley, fondly, friendly, grandly, grindley, handley, handly, hendley, hindley, hundley, kindley, kindly, lindley, pendley, profoundly, roundly, secondly, spendley, standley, unfriendly, windley
Soundly sounds like:
saintly, sandahl, sandal, sandall, sandalo, sandel, sandell, sandhill, santala, santella, santelli, santilli, santillo, santulli, scandal, scantily, schendel, schindel, schmidl, schoenthal, scintilla, secondly, sendawal, sentell, sentelle, sequential, sequentially, shindle, simental, smedley, smitley, smittle, smoothly, sundahl, sundell, sundial, swindall, swindell, swindle