Here's what rhymes with regail.
gale kale male scale fail mail sale pale sail tail tale jail nail rail veil hail shale whale bail vale wail bale dale pail quail hale quale grail faille wale detail trail avail prevail entail frail email stale assail curtail inhale snail exhale flail bewail braille derail impale lugsail carrell travail gunwale pigtail unveil wassail hightail fingernail mainsail topsail foresail martingale monorail taffrail bobtail pellmell hangnail ponytail countervail swallowtail nonpareil tattletale