This latest rumor comes from VGC which was backed up by Eurogamer. The rumor states that Mario is in for an eventiful year as several remasters and new games in the series are coming to Switch. These remasters and games are tied to the 35th anniversary of the popular plumber himself. Another rumor that has been reinforced by both outlets is the existence of a new Paper Mario game. The new Paper Mario game is supposedly coming out for Switch later this year.
*Update* Gematsu has heard reports of Super Mario 64 and Sunshine getting HD remasters on Switch.
In terms of remasters, both outlets states a Deluxe Edition of Super Mario 3D World and a Super Mario Galaxy remaster. However, please take this rumor with a grain of salt as no plans for the Mario series have been announced by Nintendo as of yet. Stay tuned at Final Weapon for the latest Japanese gaming news and rumors!