User blog comment:Exotoro/So Much Smash News/@comment-25395573-20140815145325/@comment-1414871-20140816004440

Which isn't the same as spinning off but there are a few mario references in zelda such as the pet chain-chomp and such.

Mario is the only series that really has spin-offs; the other nintendo series don't have this problem aside from maybe zelda (with it's tingle spin off games, but since those were three games that had no relation with each other and the fact tingle remains solely as an assist, I think it isn't a real problem) thus it's sort of hard to get an idea of whether they count as part of the mainline or not.

I think Donkey Kong is deattached enough, enough to get it's own little series intro in the SSB4 intro. Yoshi and Wario are a little more trickier. Wario basically only appears in the sports and karts games outside of his own games, while Yoshi has made HUGE mainline appearances as of late.

Wario has never really appeared in a mainline Mario game for a long time iirc.