4) Sarco Plank
So far, all of these characters have at least been featured in the movie for a few shots, but Sarco Plank is almost more of an Easter Egg than he is an actual character; he literally appears for just a few frames as Rey and Finn are escaping Jakku, and there’s virtually no way to notice him without utilizing the pause button. Despite that, his Wookipedia page is over 2,000 words long and believe it or not, Plank’s backstory even includes an encounter with Luke Skywalker himself.
Plank grew up on a planet called Devaron, though he was a bit of an outcast and mostly lived in the woods alone. This was pre-Order 66, and so the Jedi order was still active and Plank was aware of the location of the Jedi Temple of Eedit. Yeah, he’s an old guy.
He always wanted to loot the temple but was consistently stopped by the Empire, who had a significant presence on the planet. In addition to scavenging, Plank served as a tour guide, although mostly this was a ruse so that he could lure his wealthy clients into the middle of nowhere and kill them, claiming that they suffered an unfortunate accident on the journey.
In “The Weapon of a Jedi: A Luke Skywalker Story,” Luke lands on Devaron between the events of A New Hope and The Empire Strikes Back, and Plank decides to take him on a tour to the Temple of Eedit. The two are joined by C3PO and R2D2, and when a group of Imperials come after Skywalker, Plank throws aside his initially sinister intentions and helps in the fight. Afterwards, though, Luke learns of Plank’s plan to loot the temple, and the two duel. Skywalker wins and leaves Plank to die, but he’s able to survive and at some point moves to the planet of Jakku, presumably seeing it as a good place to hide out from all the enemies he’s made.
At Niima Outpost, Plank gains a reputation as an arms dealer, buying stolen weapons and helping to enhance them. This catches us up with those several frames in The Force Awakens. Who would have known that such a trivial character has been around since before the Battle of Yavin and has dueled with Luke Skywalker? And assuming Rey is related to Luke, that means she ran right passed someone who tried to kill her father decades earlier.
It really is a small galaxy after all.