4 letters:
gabe, gade, gael, gage, gail, gain, gait, gale, game, gape, gase, gate, gave, gays, gaze, goer

5 letters:
baier, bayar, bayer, beyer, cayer, gaber, gager, gaige, gaile, galer, galle, gamer, gator, gauer, gauge, gaver, gayle, geier, gower, goyer, guier, guyer, hayer, heyer, layer, maier, mayer, mayor, neher, neyer, payer, reier, reyer, sayer, seyer, shaer, taher, weier, weyer, zaher, gaier, geyer

6 letters:
gainer, gainor, gaiser, gaiter, gauger, gayler, gaylor, gayner, gaynor, grayer, mayher, thayer

7 letters:
gaither