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