Keller \k(el)-ler\ as a boy's name is of Old German origin, and the meaning of Keller is "cellar". Probably referred to someone whose cellar was stored with ales or wine. Also possibly (Irish, Gaelic) "dear friend".
Baby names that sound like Keller are Kyler, Collier, Collyer, Colier, Gayler, Kylar, Kylor, Cuyler and Quiller. Other similar baby names are Heller, Kellen, Kelle, Kelley and Kepler.