Despite Eric Formans daughter being the main character of That ’90s Show, Topher Grace hasnt returned for the shows second season. That 90s Show originated as a spinoff to That 70s Show, a 1998 sitcom revolving around a group of high school friends. That 90s Show follows a similar format with the next generation of teens, including some of the children of the original group, who return to Point Place, Wisconsin for more antics. That 90s Show cast and characters list grew with the addition of season 2 part 1, yet many actors have yet to return for another cameo.

https://screenrant.com/why-isnt-topher-grace-eric-forman-in-that-90-show-season-2/