Fullbacks rhymes with:
pullbacks, pricklebacks, pullbacks, rollbacks, buybacks, comebacks, cutbacks, drawbacks, flashbacks, givebacks, greenback's, greenbacks, halfbacks, kickbacks, leasebacks, leatherbacks, paperbacks, paybacks, pricklebacks, pullbacks, quarterbacks, razorback's, razorbacks, rollbacks, setbacks
Fullbacks sounds like:
fallback, felps, filipek, filipiak, filipkowski, filipovic, filipowicz, filipski, filofax, flapjack, flapjacks, flaps, flavius, flips, flops, flubs, fluffs, fullback