Here's what rhymes with planktonically.
chronically conically phonically bionically monotonically demonically mnemonically laconically sardonically electronically harmonically hydroponically ultrasonically histrionically Words that almost rhyme with planktonically
comically methodically analogically melodically historically periodically symbolically metabolically diabolically episodically knowledgeably alcoholically bucolically technologically pedagogically ethnologically lethargically prehistorically demagogically vitriolically philosophically catastrophically genealogically exorbitantly anthropomorphically