Dunno on length, but here’s the emulatable (or similar) I recommend, with what appears after the semicolons within the parenthesis (when available) being where you can get them digitally that I know:

The MacVenture series (Apple IIGS / Macintosh Classic; Steam & Humble Widgets)
Nix: The Paradox Relic (NES; Itchio)
Augury Red Code (GB; Itchio)
Castlevania: SotN (PS1; PS Vita’s PSN)
Final Fantasy VI (all versions are mostly the same)
Final Fantasy II and Crisis Core (PSP)
Anodyne (Adobe Flash; iirc all PC versions still have the Flash version)
Metal Slug 1 to 4 and X, Sonic 1 to 3 (any versions you can emulate)
Bravely Default and Bravely Second (3DS)
Böbl (NES; Itchio)
Celeste Classic and Celeste Classic 2 (PICO-8; Lexaloffle forums)
Dissidia 012 (PSP)
Ever Oasis (3DS)
Final Fantasy VII (PS1; PS Vita’s PSN)
Final Fantasy XII (PS2)
Final Fantasy XII Revenant Wings (NDS)
God Hand (PS2; PS3’s PSN)
God of War 1 and 2 (PS2)
God of War Chain of Olympus (PSP)
Godzilla Unleashed (PS2)
Avatar: The Last Airbender, The Burning Earth and Into the Inferno (PS2)
Devil May Cry 1 and 3 (PS2)
Disney’s Bolt (PS2)
Dragon Ball: Budokai Tenkaichi 2 (PS2)
GrimGrimoire (PS2)
Gunbird & Gunbird 2 (any versions you can emulate)
Ico & Shadow of the Colossus (PS2)
MegaRace (MS-DOS; GOG, Steam and Zoom Platform)
Micro Mages (NES; Itchio and Steam)
Naruto Ultimate Ninja 1 to 5 (PS2)
Nicktoons: Battle for Volcano Island (PS2)
Odin Sphere (PS2)
Okami (PS2)
Parasite Eve (PS1)
Persona 3 FES (PS2)
Phoenotopia (Adobe Flash)
Kunio-Tachi no Banka (SNES; through River City Girls 0 on Steam)
Shantae franchise (first on GBC/GBA, second on NDS, third on 3DS)
Solatorobo (NDS)
Slipways Classic (PICO-8; Itchio)
Tanglewood (Mega Drive/Genesis; GOG, Itchio and Steam)
The Fairly OddParents! Shadow Showdown (PS2)
The King of Fighters 2002 (Neo Geo; most PC versions)
The Simpsons Game (PS2)
The Simpsons Hit & Run (PS2)
VVVVVV (engine open source so several ports exist)
War of the Monsters (PS2)
Wishing Sarah (GB; Itchio and Steam)
Wonder Boy in Monster World (Mega Drive/Genesis)
コテDEメクール (PC-98; Project EGG)
Naruto Uzumaki Chronicles 1 and 2 (PS2)
Dust Bunny (PICO-8; Itchio)