Stark Industries making a toaster called "The Toast Mate 2000" as shown in the TV commercial of WandaVision's episode 1 is a fictional element created for the Marvel Cinematic Universe (MCU). The show WandaVision is a Marvel Studios production, and it features fictional commercials that are part of the show's unique storytelling style, taking inspiration from classic TV sitcoms.
In WandaVision, each episode pays homage to different eras of television, and the commercials are designed to fit the style of each respective era. The Toast Mate 2000 commercial, along with the other commercials in the series, serves as a way to explore the traumas and experiences of the show's main characters, Wanda Maximoff (Scarlet Witch) and Vision, in a symbolic and metaphorical manner.
As a result, while Stark Industries is a well-known fictional company within the Marvel universe, and they have produced various technological marvels, "The Toast Mate 2000" toaster itself and its commercial are not part of any official Stark Industries product line outside of the WandaVision show. It's a clever and creative addition to the series' narrative and world-building.