Givebacks rhymes with:
buybacks, comebacks, cutbacks, drawbacks, flashbacks, fullbacks, greenback's, greenbacks, halfbacks, kickbacks, leasebacks, leatherbacks, paperbacks, paybacks, pricklebacks, pullbacks, quarterbacks, razorback's, razorbacks, rollbacks, setbacks
Givebacks sounds like:
gaffes, gap's, gaps, gasps, gebbie's, gibas, gibb's, gibbs, gibbs's, gibes, giveaways, giveback, gives, gobs, goofs, goosefish, gopac, gopac's, gossips, govpx, govs, gozofsky, guavas, guba's, guffaws, guppies, gypsies, gypsy