Which games did you buy for Switch again which you already owned for another platform?

So far I have

• Mario Kart 8  (sold my Wii U version the day of the deluxe announcement for a good price)
• Thimbleweed Park (bought the PC version day one, added the Switch version later to support Ron Gilbert)
• Goetia (bought the Switch version after the PC version in a sale... unfortunately the fonts are way too small for mobile use)
• L.A. Noire  (my old PC version runs perfect on my cheap notebook, but I couldn't pass a €14 deal for the Switch version)

Mario Kart 8 Deluxe
Bayonetta 1 & 2
Donkey Kong Country: Tropical Freeze

I haven't double dipped n anything yet.
Think I'm one of the few who didn't rebuy MK8... waiting patiently for MK9.

BTW nice deal on LA Noire!

I rarely double dip. If anything, I buy a game I've played already through piracy, and that way I support the devs, but that's it.

• The Legend of Zelda: Breath of the Wild - I still have my Wii U version
• Mario Kart 8 Deluxe - I still have my Wii U version
• Dragon Ball Xenoverse 2 - I still have my PS4 version 
• L.A. Noire  - I still have the Steam version on PC
• Doom - I still have my Steam version on pc and i sold my ps4 version 
• The Elder Scrolls V: Skyrim - I still have the Legendary and Definitive edition on Steam/PC, on PS4 (Steelbook edition) and on my PS3 (Legendary Edition)
• Naruto Ninja Storm Trilogy - I have the separated versions of Storm 1, 2 and 3 on PS3
• Resident Evil Revelations - I still have my Steam PC version, 3ds version and Wii U version, i sold my switch version after finished the campaign.
• Resident Evil Revelations 2 - I still have my PS3 version and my Switch Version (because i redeemed the code that comes with resident evil revelations collection)
• Rayman Legends -  I still have on Ps4, i sold my Wii U version after finished the game and my Switch Version after playing just a little
• Stardew Valley - i have on Steam too
• Hollow Knight - The same thing, i have on Steam too
• Steamworld dig 2 - i have the drm free version that comes with Twitch Prime
• Oxenfree - I have on Steam

Cave Story. That was it.

Okami. Have it on the Wii. Now it's portable, has HD graphics and touch screen controls. Major win.

Okami (well it was posted from Japan on the 22/8 anyway), Rayman Legends, Skyrim and monster hunter xx (sort of... both are on switch... the Japanese import and the recently released $80 physical English language patch...)

Basically just Minecraft, Skyrim, and Doom. Though for Minecraft it's more like quadrouple dipping, since I put that on everything. Didn't have a Wii U, so those ports are all new to me.

Might double dip Civ 6 as well.

Does Bayonetta count?  It came with the first one, but I mainly got it for 2.

Mario Kart 8 Deluxe