The best family games like Conker's Bad Fur Day are Banjo-Kazooie, Banjo-Tooie and Ratchet and Clank. Below are 5, each with the reason it is here — and, at the end, what filtering to family costs you.
Filtering to family means the game has to work for a child and an adult at the same table without either of them being bored. That is a much harder design problem than a difficulty slider.
What you get: Something you can put in front of anyone. The best family games make the skill gap not matter rather than pretending it is not there.
What made Conker's Bad Fur Day worth playing in the first place is covered on the full list. This page is the family part of that answer, and only the family part.
The same team and the same engine, without the hangover.
Bigger, denser, and closer to Conker's sprawling set-piece levels.
Cartoon platforming plus real weapons, which is Conker's second half.
Sharp writing in a 3D platformer, and the levels are far stranger.
Rare's other N64 collectathon, if you want more of the same era.
Edge. Family games rarely go anywhere uncomfortable, and a few of them are too generous to hold an experienced player for long alone.
Specifically, these are strong answers for Conker's Bad Fur Day that are not family games, so they are not on this page:
The full list is on games like Conker's Bad Fur Day — 9 picks, no genre filter.
Banjo-Kazooie. The same team and the same engine, without the hangover.
No. Conker's Bad Fur Day released on the Nintendo 64, but a recommendation is only useful if you can play it, so the picks above span platforms and eras. What they share is the genre and the reason.
Age ratings cover content but not difficulty or frustration, which is what actually ruins a family session. Five minutes of unedited play footage tells you more than any rating.
With mixed ages, co-operative usually wins. The competitive ones that work are the ones where being in last place is still entertaining.
By hand. Each pick was written for the full Conker's Bad Fur Day list first, on what the game actually does, and this page is the part of that list that is family — never a genre tag lookup, which is how "best racing games like Super Mario 64" used to be a page on this site.
Or read the family guide for where to start in the genre generally.