Odyssey 2/3D Mario in 2020/2021. However, If there is a DLC announcement in the next direct, there is no 3D Mario until, like, 2023, 2024.
I think we will see a smaller scale Zelda within the next few years, and a BOTW scale Zelda towards the end of Switch's life, probably 2022 or 2023.
A new Legend of Zelda game happens usually once every 5-6 years... but I think if they take the Majora's Mask Same Engine-New Game approach, I think we could see a new game in like Mid 2021 to Early 2022. Also I think the switch is probably not going to be replaced until 2023 at the earliest and won't be discontinued until early 2025 at the earliest.
I am 95% sure Super Mario Party will get a sequel in 2019-2020, and i even think a 3rd game is, like, 50/50 for a 2021-2022 release.
Mario Kart 9 will probably have a switch release date, but I think that will be at best a Mid 2022 Release.