Washu Hakubi from Tenchi Muyo! Royo-Ohki
I had to really think about who to pick for this entry, since most female characters I like are not mothers or mother figures. And then I remembered Washu. Sure, she is not really motherly towards Ryoko, but she is a mother and I really like her character. I still haven't seen the third OVA season, where we find out more about her past, but I still think she counts.