Captain Sidon Ithano, the Blood Buccaneer, or the Crimson Corsair depending on who you ask, is one of the easier background characters to spot in The Force Awakens. Mostly because Lupita Nyong'o's Maz Kanata literally points him out to Finn when the runaway stormtrooper decides to flee rather than fight with Rey, Han, and Chewie. The red regaled pirate very nearly takes Finn aboard as part of his crew, helping him disappear into the Outer Rim.
The good captain wasn't just some random pirate, however. By the time of The Force Awakens, The Crimson Corsair had earned a reputation as the best pirate in the Outer Rim territories. His legend only continued to grow right up until the events of The Force Awakens. This is in spite of the fact that he almost never felt the need to speak -- much less boast -- about his own adventures and deeds.
The most notable such exploit was revealed in "The Crimson Corsair and the Lost Treasure of Count Dooku." During which the Delphidian outlaw, along with the rest of the hired help aboard his ship, the Meson Martinet, tracked down a crashed Separatist cruiser. Said ship was rumored to hold the titular Sith lord's lost booty. Specifically, the lightsaber crystals of every Jedi killed during the Clone Wars.
During this mission the Corsair -- almost by accident -- overcomes rival pirate gangs, and old enemies, escapes a giant sandworm, and rapidly reactivating super battle droids. To top it all off he even blows up a toxic sandstorm. What he did not do, however, was find any crystals. Instead, the party discovered the frozen -- and still breathing -- clone trooper CT-6116, aka Kix. He was of the clone troopers who had uncovered Order 66, and been captured by Count Dooku for his troubles. Which of course made him completely worthless those many, many decades after the Clone Wars.
Helping him to escape the droids, worms, and explosions anyway, Ithano seemingly sacrificed himself to the many improbable horrors after him and (what was left of) his crew. Miraculously, the captain escaped anyway, stealing a truckload of valuable Separatist data in the process.
When asked about his seemingly impossible survival, the scarlet scoundrel only said the he doesn't "die so easily." Implying that this was far from the first or last time he would escape certain doom.
Sarco Plank doesn't have nearly as much screen time in The Force Awakens as The Crimson Corsair, and that's saying something. A true background character, Plank is seen in the backdrop of Niima Outpost around Rey, Finn, and BB-8 towards the beginning of the movie. He probably never knew about the trio's ultimate mission to find Luke Skywalker. Which is ironic, given that not only Melitto bounty hunter met the Jedi knight, but nearly killed him.
The pair had met some 30-plus years earlier on the decidedly much more verdant planet of Devaron. There Plank had earned a reputation as a sadist, so much so that he was forced to live in and around the forests surrounding what civilization there was on the planet.
This was long before his bounty hunting days. From the time of the Clone Wars up to the destruction of the first Death Star, Sarco Plank was a scavenger -- technically "The Scavenger," according to the locals. Despite hating the nickname he didn't do much to shake it, earning what he could by, well, scavenging. More often he would just lead wealthy, off-world poachers to their deaths and take what he could from their bodies. All-in-all, a pretty neutral guy compared to what you often get in the Star Wars universe.
That changed when Luke Skywalker dropped by incognito. At first Plank intended to "scavenge" the Jedi's bamboozled and uncomplaining corpse. But when it became clear that Luke was after an abandoned Jedi temple he "allowed" the Jedi to live long enough to find the entrance.
Unfortunately, their tandem search alerted a contingent of Imperial troopers. "Unfortunately" for the Imperials, that is, as Luke and Plank became temporary murder buddies for the purposes of killing their shared enemies and hiding the bodies.
Thinking Luke was just a Padawan, Plank then turned on the technically-still-untrained knight. Despite having no eyes, or ears, and a face that looks like a bug's ass, Plank handily blinded and beat Luke to a pulp with his lightsaber-proof electrostaff. Luke only survived because Plank believed he wasn't a threat, and was able to sucker punch the eyeless traitor. He survived, naturally, and made his way to Jakku to become a bounty hunter and arms dealer those many years later.
It's probably a good thing, then, that Sarco didn't overhear our heroes' mission. It's doubtful his newfound career made him any more likely to forgive the Jedi that bested him.