
My buddy at the time had a 2600 Jr, and we played late 2600 games like Vanguard, Kangaroo, Mario Bros, and Solaris. Vanguard actually wasn't too bad on 2600, but I did end up getting the Atari 8-bit version, which was great.
Rampage is a classic, of course. WB actually made a successful movie out of it. It would be nice if they'd make a home video game, but they don't seem to care about anything that isn't Mortal Kombat or Wizarding World.
I didn't play Dragon Warrior until my friend got it. I have always felt that Dragon Quest on NES was better than Final Fantasy on NES.
My favorite game of 1986 is Starflight, a PC space sim from EA and Binary Systems. It nailed the Star Trek experience better than any licensed Star Trek game ever did. Its modern spiritual successor is No Man's Sky.