I don’t think I could just limit my candidates to three. One of my personal criteria is that the game was awesome when released (one of those games I kept obsessing about, outside gaming time), but is also good now when replayed (discounting the typical gameplay QoL improvements since then). Several really good games do that for me (in no particular order):

• Silent Hill 2
• Morrowind
• Terranigma
• Bloodborne
• Chrono Trigger
• Half-Life
• Baldur’s Gate 2
• Pokémon Crystal
• Shin Megami Tensei: Nocturne
• Tactics Ogre
• Ultima 6
• Vampire the Masquerade: Bloodlines … and many others.

Most of them are old, mainly because I don’t know if my modern favorites will pass the test of time in 10 years (games like Crimson Desert, Control, Lies of P or Wuchang).