When redditor TheRybka came across this old red motorcycle in Fallout 4, he noticed a small nod to Fallout 3. Look closely at the name of the bike.
It's hard to see so I adjusted the brightness and zoomed in.
The wasteland motorcycle is appropriately named Lone Wanderer, which was also the name of the Fallout 3 protagonist.
Feeling lost without the G.O.A.T.? Take a trip to the town of Covenant where you'll be forced to pass a test to prove you're a "good" person. What's the test? A repurposed G.O.A.T. A man named Swanson sits you down and asks you modified G.O.A.T. questions. And with his leather jacket and coifed hair, he looks like he belongs in the Tunnel Snakes.
Here's a youtube video in case you hate surprises and love spoilers:
If you're spending most of your time in the Commonwealth hunting for Good Will Hunting easter eggs, then you're in luck. Within the Cit Rotuna, you can find the greatest work of Will Hunting. And I don't mean the mop job he did -- I mean, look at how clean this place is, you could eat off the floor (as long as you're a cannibal who's immune to radiation).
Check out the symbols on the chalkboard.
It's like Will Hunting is there, yelling in your face: "You like easter eggs? Well, I got her number, so how do you like 'em easter eggs?"
Like Fallout 3, Fallout 4 has included many teddy bears you can find in interesting positions.
These toy blocks spell out the name of Gary, everybody's favorite clone (or clones) from Fallout 3. In the previous installment, you could explore Vault 108, which was overrun by bloodthirsty Gary clones, the test subjects of a failed cloning experiment.