Beat me to it.
There are plenty of mothers in videogames, but it sure seems less relevant than the mostly recent trend of gruffy, badass fathers with a young rebellious child. Amnesia: Rebirth, (the following is a spoiler for a very well known Walking Sim you will know if you've played it) of which is a very relevant part of the game. Bayonetta (sorta), Sindel from Mortal Kombat are a few relevant examples (somebody else mentioned Selan in Lufia 2, good shout). Not relevant to the plot, well, many characters, too much to count, to whom motherhood is irrelevant to the plot or mechanics.
This is a weird trope. I felt this happened back in the nineties with characters like Terra and Celes from FFVI. Recently I had this issue with the TV Series The Chilling Adventures of Sabrina, where Sabrina is oddly maternal to all of her friends. Remember Pokémon? The series where they turned 12 year old Misty into a mother with Togepi? Maybe this is common in some sort of media. It kinda irks me, for some reason, but I am not sure it should.Does Claire Redfield count?
In all of her roles she's always playing a maternal role to someone (even steve burnside)
Mothers and women that aren't ace or bi are almost nonexistent as main characters sadly.
True, though I'm not sure how their sexual oritentation is relevant here.
Does this count? In that case, there might be more.