I've been adding games by year, going backward, and most of the games I found that are missing are mobile games, Japanese exclusive games, or old PC games.

Here's what I found so far that's missing:

Final Fantasy Awakening (Mobile, 2018) https://en.wikipedia.org/wiki/Final_Fantasy_Awakening
Please Knock on My Door (PC, 2017) https://store.steampowered.com/app/613450/Please_Knock_on_My_Door/
Melobeat (Mobile, 2017) https://play.google.com/store/apps/details?id=com.float32.themelobeat&hl=en_US
Sonic Forces: Speed Battle (Mobile, 2017) http://sonic.wikia.com/wiki/Sonic_Forces:_Speed_Battle
Animal Crossing Pocket Camp (Mobile, 2017) https://ac-pocketcamp.com/en-US/site
Final Fantasy XV: A New Empire (Mobile, 2017) https://www.finalfantasyxvapp.com/#home
Pokemon Go (Mobile, 2016) https://pokemongolive.com/en/
Mystic Messenger (Mobile, 2016) https://play.google.com/store/apps/details?id=com.Cheritz.MysticMessenger&hl=en_US
Final Fantasy Portal App / Triple Triad (Mobile, 2015) https://play.google.com/store/apps/details?id=com.square_enix.ffportal_w.googleplay&hl=en_US
Final Fantasy Record Keeper (Mobile, 2015) https://www.finalfantasyrecordkeeper.com/
Agar.io (PC, 2015) https://agar.io/
Lost Constellation (PC, 2014) http://nightinthewoods.wikia.com/wiki/Lost_Constellation
Longest Night (PC, 2013) http://nightinthewoods.wikia.com/wiki/Longest_Night_(Game)
Puella Magi Madoka Magica Portable (PSP, 2012) https://wiki.puella-magi.net/Puella_Magi_Madoka_Magica_Portable
Hunter x Hunter: Wonder Adventure (PSP, 2012) https://hunterxhunter.fandom.com/wiki/Hunter%C3%97_Hunter_Wonder_Adventure
Pokemon Trading Card Game Online (PC, 2011) https://www.pokemon.com/us/pokemon-tcg/play-online/
Mighty Switch Force! (3DS, 2011) https://en.wikipedia.org/wiki/Mighty_Switch_Force!
Case Closed: The Mirapolis Investigation (Wii, 2009) https://en.wikipedia.org/wiki/Case_Closed:_The_Mirapolis_Investigation
Kateikyoushi Hitman Reborn Battle Arena 2 - Spirits Burst (PSP, 2009) http://reborn.wikia.com/wiki/Kateky%C5%8D_Hitman_Reborn!_Battle_Arena_2_-_Spirits_Burst
Shin Megami Tensei: Imagine (PC, 2008) https://en.wikipedia.org/wiki/Shin_Megami_Tensei:_Imagine
osu! (PC, 2007) https://osu.ppy.sh/home
Battle Stadium D.O.N. (GCN, 2006) https://en.wikipedia.org/wiki/Battle_Stadium_D.O.N
One Piece Going Baseball - Kaizoku Yakyuu (GBA, 2004) https://gamefaqs.gamespot.com/gba/919374-one-piece-going-baseball-kaizoku-yakyuu
Mavis Beacon Teaches Typing 15.0 (PC, 2003) https://www.amazon.com/Mavis-Beacon-Teaches-Typing-VERSION/dp/B00006IFST
Jennifer Government: NationStates (PC, 2002) https://www.nationstates.net/
Kuru Kuru Kururin (GBA, 2001) https://en.wikipedia.org/wiki/Kuru_Kuru_Kururin
Quest for Camelot (GB, 1998) https://gamefaqs.gamespot.com/gbc/367105-quest-for-camelot/faqs
Airline Tycoon (PC, 1998) https://en.wikipedia.org/wiki/Airline_Tycoon
Fisher-Price Time to Play Dollhouse (PC, 1998) https://www.amazon.com/Fisher-Price-Time-Play-Dollhouse-PC/dp/B00005KG5D
D.W. the Picky Eater / Arthur's Adventures with D.W. (PC, 1998) https://arthur.fandom.com/wiki/D.W._The_Picky_Eater_(game)
My First Amazing World Explorer 2.0 (PC, 1998) https://www.amazon.com/First-Amazing-World-Explorer-2-0/dp/B00002S968
Arthur's Reading Race (PC, 1997) http://livingbooks.wikia.com/wiki/Arthur%27s_Reading_Race
Hourai Gakuen no Bouken! (SNES, 1996) https://gamefaqs.gamespot.com/snes/580884-horai-gakuen-no-bouken
Dragon Ball Z: Hyper Dimension (SNES, 1996) http://dragonball.wikia.com/wiki/Dragon_Ball_Z:_Hyper_Dimension
Radical Dreamers (SNES, 1996) https://en.wikipedia.org/wiki/Radical_Dreamers
Super Jinsei Game 3 (SNES, 1996) https://gamefaqs.gamespot.com/snes/580894-super-jinsei-game-3
Hollywood High (PC, 1996) https://en.wikipedia.org/wiki/Hollywood_High_(video_game)
Sailor Moon SuperS: Zenin Senkai! Shuyaku Soudatsusen (SNES, 1996) https://sailormoon.fandom.com/wiki/Bishoujo_Senshi_Sailor_Moon_SuperS:_Zenin_Sanka!!_Shuyaku_Soudatsusen
Wishbone and the Amazing Odyssey (PC, 1996) https://www.amazon.com/Wishbone-Amazing-Odyssey-Win-Mac-pc/dp/B0006BKN5A
Sim Park (PC, 1996) https://en.wikipedia.org/wiki/SimPark
Mobile Suit Gundam Wing: Endless Duel (SNES, 1996) http://gundam.wikia.com/wiki/Mobile_Suit_Gundam_Wing:_Endless_Duel
JumpStart Adventures 4th Grade: Haunted Island (PC, 1996) http://jstart.wikia.com/wiki/JumpStart_Adventures_4th_Grade:_Haunted_Island
JumpStart 2nd Grade (PC, 1996) http://jstart.wikia.com/wiki/JumpStart_2nd_Grade
Dragon Ball Z: Super Gokuden: Kakusei-Hen (SNES, 1995) http://dragonball.wikia.com/wiki/Dragon_Ball_Z:_Super_Gokuden:_Totsugeki-Hen
Super Jinsei Game 2 (SNES, 1995) https://www.giantbomb.com/super-jinsei-game-2/3030-54003/
Slam Dunk SD Heat Up!! (SNES, 1995) https://gamefaqs.gamespot.com/snes/571369-from-tv-animation-slam-dunk-sd-heat-up
Hollywood (PC, 1995) https://en.wikipedia.org/wiki/Hollywood(video_game)
Thinkin' Things 3 (PC, 1995) https://www.giantbomb.com/thinkin-things-collection-3/3030-2813/
Imagination Express: Rainforest (PC, 1995) http://www.cdaccess.com/html/shared/d-rain&c.htm
Tenchi Muyou! Game Hen (SNES, 1995) https://en.wikipedia.org/wiki/Tenchi_Muyo!_Game_Hen
JumpStart 1st Grade (PC, 1995) https://en.wikipedia.org/wiki/JumpStart_1st_Grade
3D Pinball: Space Cadet (PC, 1995) https://classicreload.com/win9x-3d-pinball-space-cadet.html
Ballz 3D: Fighting at its Ballziest (Genesis, 1994) https://www.giantbomb.com/ballz-3d-fighting-at-its-ballziest/3030-1942/
Storybook Weaver (PC, 1994) https://en.wikipedia.org/wiki/Storybook_Weaver
Dragon Ball Z: Buyu Retsuden (Genesis, 1994) https://en.wikipedia.org/wiki/Dragon_Ball_Z:_Buy%C5%AB_Retsuden
Yuu Yuu Hakusho: Tokubetsu Hen (SNES, 1994) https://gamefaqs.gamespot.com/snes/564158-yuu-yuu-hakusho-tokubetsu-hen/faqs
Yu Yu Hakusho 2 Kakutou no Shou (SNES, 1994) https://gamefaqs.gamespot.com/snes/564285-yuu-yuu-hakusho-2-kakutou-no-sho
Ranma ½: Chougi Rambuhen (SNES, 1994) https://gamefaqs.gamespot.com/snes/588601-ranma-1-2-chougi-ranbu-hen
Thinkin' Things 2 (PC, 1994) https://www.giantbomb.com/thinkin-things-collection-2/3030-16522/
The Magic School Bus Lost in the Solar System (PC, 1994) https://en.wikipedia.org/wiki/The_Magic_School_Bus_Lost_in_the_Solar_System
Imagination Express: Neighborhood (PC, 1994) https://www.amazon.com/Imagination-Express-Destination-Neighborhood-Edmark/dp/B002AXT0G0
The Busy World of Richard Scarry Busytown (PC, 1994) https://www.giantbomb.com/richard-scarrys-how-things-work-in-busytown/3030-41024/
Nickelodeon Directors Lab (PC, 1994) https://www.ebay.com/p/Nickelodeon-Directors-Lab-PC-1994/170281913
Sammy's Science House (PC, 1994) https://classicreload.com/dosx-sammys-science-house.html
Imagination Express: Castle (PC, 1994) https://www.amazon.com/Destination-Castle-IMAGINATION-EXPRESS/dp/B001JD8HLG
Arthur's Birthday (PC, 1994) https://arthur.fandom.com/wiki/Arthur%27s_Birthday_(game)
Treasure Cove! (PC, 1994) https://en.wikipedia.org/wiki/Treasure_Cove!
SD Hiryuu no Ken (SNES, 1994) https://en.wikipedia.org/wiki/Hiry%C5%AB_no_Ken
Shelley Duwall Presents Digby's Adventures: Tales of a 1-Pound Dog (PC, 1994) http://www.museumofplay.org/online-collections/22/66/109.10939
Chavez II (SNES, 1994) https://snescentral.com/article.php?id=0109
Chavez (SNES, 1994) https://snescentral.com/article.php?id=0277

A few games from Hamumu software (indie stuff, surprisingly fun!)
Dev website : http://hamumu.com/games.php

For each game I've included the cover picture in another link, since it is not on the same page but on the game selection page.

Kid Mystic (aka Spooky Castle : The Adventures of Kid Mystic)
https://hamumu.itch.io/kid-mystic
https://img.itch.zone/aW1hZ2UvMjA2NDYzLzk2NjY5Ny5wbmc=/180x143%23c/NCKgQK.png

Dr. Lunatic Supreme with Cheese
https://hamumu.itch.io/dr-lunatic-supreme-with-cheese
https://img.itch.zone/aW1hZ2UvMjA1NzYyLzk2MjYxMy5qcGc=/180x143%23c/AL7F8h.jpg

Loonyland: Halloween Hill
https://hamumu.itch.io/loonyland-halloween-hill
https://img.itch.zone/aW1hZ2UvMjA2MTU1Lzk2NTI0OS5wbmc=/180x143%23c/nFpg04.png

Loonyland 2: Winter Woods
https://hamumu.itch.io/loonyland-2-winter-woods
https://img.itch.zone/aW1hZ2UvMjA2ODA5Lzk2ODk2MC5wbmc=/180x143%23c/n4voT3.png

Sleepless Hollow (aka The Adventures of Bouapha: Sleepless Hollow)
https://hamumu.itch.io/sleepless-hollow
https://img.itch.zone/aW1hZ2UvMjA3ODU1Lzk3NDE1OC5wbmc=/180x143%23c/%2FF2EUe.png

Spooky Castle (aka The Adventures of Bouapha: Spooky Castle)
https://hamumu.itch.io/spooky-castle
https://img.itch.zone/aW1hZ2UvMjEyNDQyLzEwMDA1NzAucG5n/180x143%23c/nz9QRe.png

There are others by the dev, but these are the ones I like. :D

@psychoapeguy and @Nocmin - Those have all been added!

@Sarena - I've started working on your list, but it might take a few days to get 'em all loaded!

Bad North

@blacksheeptrp8 - That has been added!

Got 2 compilations, so moho may have to handle these...

Yomawari: The Long Night Collection https://gamefaqs.gamespot.com/switch/240105-yomawari-the-long-night-collection
Kingdom Hearts: The Story So Far https://gamefaqs.gamespot.com/ps4/249533-kingdom-hearts-the-story-so-far

@Sarena - I think I added all of the ones on your list, let me know if I missed any!

@psychoapeguy - Those have both been added!

Amiibos Coming Soon, Like Ice Climbers, King K Rool etc

@blacksheeptrp8 - All of the upcoming Amiibo should be on here now!

Jill of the Jungle (Trilogy)

Currently free on gog.com, but not in the database.

https://www.gog.com/game/jill_of_the_jungle_the_complete_trilogy

https://en.wikipedia.org/wiki/Jill_of_the_Jungle

Call of Duty Classic on PS3 :

https://store.playstation.com/en-us/product/UP0002-NPUB30065_00-CODCLSSICLICENCE

@shiftyphil and @Marcelloz - Those have both been added!

Mario + Rabbids Kingdom Battle: Donkey Kong Adventure
https://www.mariowiki.com/Donkey_Kong_Adventure

@Lucoshi - That has been added!

Egypt: Old Kingdom (newly released on GOG: https://www.gog.com/game/egypt_old_kingdom)

Mutant Mudds Collection ( https://www.nintendo.com/games/detail/mutant-mudds-collection-switch ) consisting of:
- Mutant Mudds Deluxe - https://completionator.com/Game/Details/1116
- Mutant Mudds Super Challenge - https://completionator.com/Game/Details/34082
- Mudd Blocks - not in database

DELTARUNE Chapter 1: https://www.deltarune.com/
its free and its made by toby fox, the guy behind Undertale

@Dub Conqueror - That has been added!

Steam Games

TSIOQUE
Capcom Beat 'Em Up Bundle

Ultima Trilogy I-II-III https://gamefaqs.gamespot.com/appleii/225562-ultima-trilogy
Ultima The Second Trilogy IV-V-VI https://gamefaqs.gamespot.com/pc/195759-ultima-the-second-trilogy
Generation of Chaos https://gamefaqs.gamespot.com/ps2/924875-generation-of-chaos
Generation of Chaos Desire https://gamefaqs.gamespot.com/ps2/941622-generation-of-chaos-desire
Generation of Chaos III: Toki no Fuuin https://gamefaqs.gamespot.com/ps2/916729-generation-of-chaos-iii-toki-no-fuuin
Generation of Chaos Next https://gamefaqs.gamespot.com/ps2/567282-generation-of-chaos-next
Generation of Chaos Exceed https://gamefaqs.gamespot.com/gamecube/583458-generation-of-chaos-exceed/images/124511
Gensou Tairiku Auleria https://gamefaqs.gamespot.com/turbocd/589306-gensou-tairiku-auleria
Gloria Union https://gamefaqs.gamespot.com/psp/626012-gloria-union
God Medicine: Fantasy Sekai no Tanjou https://gamefaqs.gamespot.com/gameboy/569824-god-medicine-fantasy-sekai-no-tanjou

• The Ultima Trilogies are just compilations of their respective games.
• Generation of Chaos is not the same game as the one for PSP, though they are part of the same series. (The game on PSP is also known as Generation of Chaos IV.)
• Generation of Chaos Exceed is just a GC port of the PS2 original with additional features.

Thank you!

@Scrunge - TSIOQUE was added!

@AllRoCol - That has been added!

Amnesia (1986)
https://en.m.wikipedia.org/wiki/Amnesia(video_game)

@everyone - I think everything should be added now!

SNK 40th Anniversary Collection - Nintendo Switch - https://gamefaqs.gamespot.com/switch/236359-snk-40th-anniversary-collection

11-11 Memories Retold
https://store.steampowered.com/app/735580/1111_Memories_Retold/