Mammoth Uncensored Word List:
43 words ending with ys, 4 letters long

abys bays boys buys cays coys days deys doys drys feys foys gays goys guys hays heys hoys jays joys kays keys lays leys loys mays moys nays noys pays prys puys rays says seys soys tays toys ueys ways weys whys yays