Existing rhymes with:
coexisting, preexisting, coexisting, preexisting, coexisting, preexisting, resisting, assisting, coexisting, consisting, delisting, enlisting, insisting, listing, persisting, preexisting, resisting, thristing, twisting
Existing sounds like:
ecosystems, eighteen's, eighteens, ejecting, equating, equations, esteem's, estonians, exacting, exactions, exceeding, exciting, executing, executions, exhausting, existence, exiting, extinguish, exuding