Valeria Richards is the second child of Sue Storm and Reed Richards, and she's also the goddaughter of Victor von Doom, who named her after assisting with the delivery since Reed was away or something.

Ideally, she's just there post-Secret Wars, and in a second Fantastic Four movie, they reveal her relation to Doom, which is a major part of the character as she's kind of the one person Doom loves (as family not in a weird way). In recent comics, she's been the voice of reason for Doom and he actually left her his entire estate in the new The Will Of Doom comic, so that's how close they are. I hope we see Valeria in the MCU some time soon, I don't think she'll be in Doomsday/Secret Wars, and the only ties between the Fantastic Four and Doom in that will be the Redd/Victor rivalry, not Valeria.
When could we see Valeria Richards in the MCU?