https://www.polygon.com/2019/1/10/18177410/new-super-mario-bros-u-deluxe-blue-toad-playable-characters

When New Super Mario Bros. U Deluxe (whew!) launches on Nintendo Switch tomorrow, players of the Wii U original will be happy to find that reports of Blue Toad’s death have been greatly exaggerated.

The Wii U version of New Super Mario Bros. U featured four playable characters: Mario and Luigi, of course, alongside two Toads — one yellow, one blue. But with the Deluxe version’s addition of a playable Toadette, it seemed like Blue Toad had been thrown out of the picture. He no longer appeared in any marketing material, replaced by Yellow Toad and newcomers Toadette and Nabbit.