I don’t tend to bother with 100%ing or trophy collecting, however I did 100% Crash 2 and 3 with some buddies in college (trading off levels and lives and the like) and that was tons of fun (though I’d beaten the games on my own years before).

Anyway, here’s everything I’m certain I’ve “beaten”:

BioShock
Crash Bandicoot 2: Cortex Strikes Back (PS1)
Crash Bandicoot: Warped
Enter the Matrix
Fallout 3
Fallout: New Vegas
Fallout 4
flOw
Flower
Ghostbusters: The Video Game
God of War
God of War II
God of War III
Grand Theft Auto V
Journey
Mass Effect
Mass Effect 2
Mass Effect 3
Mass Effect: Andromeda
Metal Gear (MSX version)
Metal Gear 2: Solid Snake
Metal Gear Solid (PS1 and The Twin Snakes GC remake)
Metal Gear Solid 2: Sons of Liberty
Metal Gear Solid 3: Snake Eater
Metal Gear Solid 4: Guns of the Patriots
Metal Gear Solid V: Ground Zeroes (still yet to finish TPP)
NieR: Automata
Ratchet & Clank Future: Tools of Destruction
Ratchet & Clank Future: Quest for Booty
Spyro the Dragon
Spyro 2: Ripto’s Rage
Spyro: Year of the Dragon
Star Wars: Battlefront II (original)
Star Wars: Bounty Hunter
Star Wars: Dark Forces II: Jedi Knight
Star Wars: Jedi Knight: Mysteries of the Sith
Star Wars: Jedi Knight II: Jedi Outcast
Star Wars: Jedi Academy
Star Wars: X-wing Alliance
Tomb Raider (reboot)
The Walking Dead: Season 1
The X-Files (PS1 point-and-click)

Games I either don’t know if I finished, that I didn’t finish but played so much that I feel like I have, or that aren’t really “finishable” but that I played enough that there’s no reason not to list them:

Age of Empires
Age of Empires II
ATV: Offroad Fury
ATV: Offroad Fury 2
Crash Team Racing
Gran Turismo 2
Marvel: Ultimate Alliance 2
RollerCoaster Tycoon
RollerCoaster Tycoon 2
SimCity 3000
SimCity 4
The Simpsons: Hit and Run
Sonic the Hedgehog 2
Star Wars: Battlefront (original)
Star Wars: Jedi Power Battles
Star Wars: Rogue Squadron I: Rogue Leader
Star Wars: X-wing vs. TIE Fighter

I’ll add more as more come to me.