In a recent episode of the reboot of DuckTales, it was revealed that the Disney Afternoon show Goof Troop and the spin-off film A Goofy Movie are considered canon within that universe, according to an article by CBR.
In the Season 3 episode, “Quack Pack”, the characters become trapped in an alternate reality where their neighbor is Goofy, specifically the version from the Goof Troop show. It is also shown what becomes of Goofy’s son, Max and his girlfriend Roxanne.
Read: TRON: A Retrospective
The original show DuckTales premiered in 1987 and was part of the Disney Afternoon block for several years. Other shows included on this block were Chip ‘n Dale: Rescue Rangers, Darkwing Duck, and Goof Troop. A Goofy Movie, a spin-off of Goof Troop, was released in theatres in 1995, with a direct-to-video sequel released in 2000. A reboot of DuckTales premiered in 2017 and is currently in its third season.
Both the original and reboot of DuckTales can be found on Disney+ alongside Goof Troop, A Goofy Movie, and other Disney Afternoon programs.