So here's a question prompted by all the villain talk.
Smash now has Bowser, Jr., The Koopalings, King K. Rool, Ganondorf, Ridley, Dark Samus and Wolf in Smash.
(Smash also has Meta Knight, King Dedede and Mewtwo but I am not counting them as villains.)
Who is the biggest Nintendo owned villain that isn't playable in Smash?
Probably Giovanni? And maybe Giygas?
As for Nintendo series without villains in yet, there is Kid Icarus(Medusa and Hades), Fire Emblem(the notable ones being Medeus, Gharnef, Black Knight, Grima, and
THSpoilers) Pikmin(Plasma Wraith), F-Zero(Black Shadow), Earthbound/Mother(Porky and Giygas), Xenoblade(Zanza and Malos), Splatoon(Octavio) and ARMs(Dr. Coyle).
And for series with villains, there's the multitude of Mario villains like King Boo and Fawful, Zelda villains like Ghirahim and Vaati, Kirby villains like Dark Matter, Marx and Magalor, Metroid villains like Kraid and Mother Brain, and Andross from Star Fox.
But Giovanni is probably the last big Nintendo villain not yet in Smash and he's most likely not going to be in due to Pokemon focusing on the Pokemon for characters.
As for Giygas, not a lot of people have played his game, but Giygas is incredibly popular among Top 10 lists of being one of the scariest, possibly the scariest, Nintendo bosses. Heck, he's been mentioned by a bunch of popular youtubers like AVGN and Markiplier(who he himself loves Earthbound). Chances are that most people who know Giygas haven't played his game, but have heard of him from videos.