Mobile games you can play in your browser without ads via YouTube: https://www.youtube.com/playables
Please let me know if you add any to IGDB, the vast majority currently aren't on there. Last updated June 10 2024

Not on IGDB (company given if the name is particularly generic):
Basketball FRVR
Block Drop (GameSnacks)
Brain Out (Focus Apps)
Bubble Pop Star
Cannon Balls 3D (Famobi)
Cards of the Undead
Carrom Clash (GameSnacks)
Chess Classic (Famobi)
Collect Em All! (Voodoo)
Color Burst 3D (VAEV inc)
Color Match (SuperSonic / Carawell)
Color Page ASMR
Color Pixel Art (Famobi)
Crazy Caves (Famobi)
Cube Master 3D
Cube Tower (GameSnacks)
Daily Solitaire (Arkadium)
DOP 2: Delete One Part
Draw Climber (Voodoo)
Element Blocks (Famobi)
Emoji Puzzle (SuperSonic / Fun Velikan)
Find Out (Focus Apps)
Flow Legends
Fork N Sausage
FreeCell Solitaire (Arkadium)
Freekick Football (GameSnacks)
Fullspeed Racing (GameSnacks)
Gin Rummy (GameSnacks)
Gold Mahjong FRVR
Idle Restaurants (GameSnacks)
Jewels Planet (Teskin Games)
Knock'em All (Voodoo)
Ludo Karts
Lunch Box Ready
Makeup Kit - Color Mixing
Mechangelion - Robot Fighting
Merge Heroes (GameSnacks)
Merge Pirates (GameSnacks)
Moving Co. (GameSnacks)
My Space Pet (GameSnacks)
Northern Heights (GameSnacks)
Onet Connect Classic (Famobi)
Phone Case DIY
Pirate Pop (GameSnacks)
Pocket Battle Royale (GameSnacks)
Pocket Champions (GameSnacks)
Rainy Boba Cafe (Google)
Retro Drift (GameSnacks)
Scooter Xtreme
Sculpt People
Slice It All! (Voodoo)
Stack Bounce (GameSnacks)
State.io (Casual Azur)
Super Goal (Gamegou)
Tile Master (Higgs Studio)
Today's Hurdle (Arkadium)
Turbo Stars
Wood Nuts & Bolts
Words of Wonders (Famobi)
Words of Wonders: Guru
Zoo - Happy Animals