Unshackle rhymes with:
shackle, cackle, crackel, crackle, grackle, hackel, hackl, hackle, jackal, jackel, jakel, kachel, mackall, mackel, racal, rachal, shackle, tackle, yackel, yakel
Unshackle sounds like:
unanimously, uncle, uncoil, uncool, uneasily, unequal, unglue, unicycle, uniquely, unocal, unseal, unsell, unusual, unusually, unwisely