I actually read the news on the Switch news service for once and it had a list of the top 20 most played games on Switch since launch. The ranking is based on "the cumulative number of hours that North American players have spent in-game".
Now if only Nintendo would give us a clear, exact list of how much we have played each of our own games like we had back on the... wait, which was the last one to do that? 3DS?
20. Rocket League
19. Disgaea 5 Complete
18. FIFA 18
17. 1-2-Switch
16. Pokken Tournament DX
15. Sonic Mania
14. LEGO CITY Undercover
13. Fire Emblem Warriors
12. Dragon Ball Xenoverse 2 for Nintendo Switch
11. NBA 2K18
10. The Binding of Isaac: Afterbirth+
9. The Elder Scrolls V: Skyrim
8. ARMS
7. Mario + Rabbids Kingdom Battle
6. Stardew Valley
5. Minecraft: Nintendo Switch Edition
4. Splatoon 2
3. Mario Kart 8 Deluxe
2. Super Mario Odyssey
1. The Legend of Zelda: Breath of the Wild
URL to share (right click and copy)