Bald and Beautiful Barbie
Thanks to the parents behind the Beautiful and Bald Barbie Facebook campaign encouraging Mattel to make a doll for young people who've lost their hair due to illness, the company released a bald friend of Barbie's in 2013. The doll came with wigs, scarves, and hats was only available in hospitals. One mom has a Change.org petition for Mattel to make more, but for parents looking for an alternative, MGA released bald Bratz dolls.
Source: Adventures in Child Life