Lately Nintendo has had some great collaborations with third parties, resulting in stuff like Hyrule Warriors with Koei Tecmo, the surprise hit of Mario + Rabbids with Ubisoft, moving Super Smash Bros. forward with Bandai Namco, but who's worked best with Nintendo?
For me it would be Bandai Namco, for helping out with not just Smash for 3DS and Wii U, but giving us Pokken Tournament and now working on Smash Bros. Ultimate. :)
Which third party do you think has done best with Nintendo though?