Willo is not commonly used as a baby girl name. It is not listed within the top 1000. In 2012, within the family of girl names directly related to Willo, Willow was the most popular.
Baby names that sound like Willo include Willow (English), Wyllo, Wyllow, Wylo, Walli (German), Wallie, Wally, Whaley, Wiley, Wili, Wilie, Willa (English and German), Willi (English), Willie (English), Willy (English), Wily, Wyley, Wyli, Wylie, and Wyly.
† approx English pronunciation for Willo: W as in "we (W.IY)" ; IH as in "it (IH.T)" ; L as in "lay (L.EY)" ; OW as in "oak (OW.K)"