The Switch will have no backwards compatibility with Wii U discs or 3DS cartridges, no comment on mobile games : r/wiiu
Amazon.com: Gamecube Controller Adapter for Switch/Switch OLED.Gamecube Adapter Compatible with PC Wii U.Adapter with 4 Ports 6 FT(1.8M) Cable Support Turbo and Vibration Features Super Smash Bros : Video Games
Nintendo Addresses Lack of Switch Backwards Compatibility - IGN
Amazon.com: Nyko Retro Controller Hub Plus - Gamecube Controller Adapter for Nintendo Switch, Connect up to 4 Controllers with Turbo and Home Button, Compatible with Super Smash Bros : Everything Else
Amazon.com: UGREEN Ethernet Adapter USB to 10 100 Mbps Network Adapter RJ45 Wired LAN Adapter for Laptop PC Compatible with Nintendo Switch Wii Wii U MacBook Chromebook Surface Windows macOS Linux (Black) :
Is Nintendo Switch Backwards Compatible? Can you play Wii, Wii U or 3DS games? - Daily Star
Nintendo Switch Backwards Compatibility Explained
Nintendo Switch Is Not Backwards Compatible With Physical 3DS or Wii U Games - GameSpot
Nintendo Switch not backwards compatible with physical 3DS or Wii U games | Shacknews
Nintendo Switch Not Backwards Compatible With Physical 3DS or Wii U Games - IGN
Can You Play Nintendo Wii Games on the Nintendo Switch?
Nintendo President: Backward compatibility for controllers 'may be considered' for Switch – Destructoid
How Nintendo Switch Backwards Compatibility Works - GameSpot
Nintendo Switch vs. Wii U
4-Port Controller Adapter for GameCube® Compatible with Nintendo Switch® / Wii U® / PC/ Mac®
Is the Nintendo Switch Backwards Compatible with Virtual Console, 3DS or Wii U games? - GamingDeals.com
La Nintendo Switch compatible avec la 3DS et la Wii U? - GeekQc.ca