Breath of the Wild (P) +DLC
Mario Kart 8 Deluxe (P)
ARMS (P)
Splatoon 2 (P)
Labo Variety Kit (P)
Super Mario Odyssey (P)
1-2 Switch (P)
Arcade Archives: Punch-Out! (D)
SnipperClips (D)
Picross: S (D)

20 third party games: 1 physical, 19 digital

One more digital third party game for me (Mega Man X Legacy Collection 2).

First party titles:

Breath of the Wild
Mario Kart 8
Super Mario Odyssey
Fire Emblem Warriors 
Xenoblade Chronicles 2

All were purchased physically.

I own 10 switch games overall.

Just purchased Captain Toad: Treasure Tracker (physical).

Got 3 new games recently :

- Mario Tennis Aces (P)
- Octopath Traveler (P)
- Ys VIII (P)

I don't have many first party titles surprisingly:

-Super Mario Odyssey
-Mario Kart 8 Deluxe

And I own 19 games.

First-party I have 8:

Super Mario Odyssey (P)
The Legend of Zelda: Breath of the Wild (P)
Splatoon 2 (P)
Mario Kart 8 Deluxe (D)
Snipperclips (D)
Arcade Archives: Donkey Kong (D)
Super Smash Bros. Ultimate (D)
Super Mario Party (P) (These last two on pre-order)
 
Third-party wise, I have 18.
Puyo Puyo Tetris (D)
Octopath Traveller (D)
Yodanji (D)
Crash Bandicoot N-sane Trilogy (D)
Ambition of the Slimes (D)
Fire Emblem Warriors (P)
NBA Playgrounds (D)
Shaq-Fu (D)
Overcooked (D)
Overcooked 2 (D)
Okami (D)
The World Ends With You (P) (on pre-order)
Bayonetta (D)
Bayonetta 2 (D)
Mario + Rabbids (P)
Golf Story (D)
Unholy Heights (D)
Shovel Knight Treasure Trove (D)

I have new:

Physical:
Octopath Traveler
Sonic Mania Plus
Shining Resonance Refrain
Blazblue Cross Tag Battle
Mario Tennis Aces

Digital:
Galak-Z (dunno if it counts)
Fortnite (dunno if it counts)

One more digital third party game for me (Gungeon).