Collisions rhymes with:
decision's, decisions, division's, divisions, divisions', envisions, incisions, provisions, recisions, rescissions, revisions, vision's, visions
Collisions sounds like:
calgene's, calkins, callousness, caulking, caulkins, chalking, clackamas, clashing, classing, clausing, clicking, cloaking, clocking, clogging, closeness, closing, closings, clucking, coalescence, coalescing, collegians