Stilt-Man's costume is visible behind Daredevil when he goes to collect his new helmet.
In the scene where Daredevil is getting his helmet, there is a poster on the wall in the background of what appears to be an Italian movie about a gladiator. The movie poster strongly resembles the cover to "Daredevil" (vol.1) #226 (the gladiator's costume, the pose of the two characters).
When Daredevil picks up his new helmet and gloves, Melvin Potter opens his shirt for a moment showing the reinforced suit he's wearing underneath. The lines of the Gladiator costume he wears in the Marvel comics are visible.
Daredevil Season 2 contains Tony Curran's (Finn, the Irish mob boss) second role in the Marvel Cinematic Universe (and fourth in Marvel-based productions). He had previously played Bor, father of Odin in Thor: The Dark World (2013) as well as "Man In Black Suit Agent" in X-Men: First Class (2011) and a priest in Blade II (2002).
Tony Curran is the fifth actor from Doctor Who (2005) (Having first appeared as Vincent VanGogh in Vincent and the Doctor (2010)) to enter the Marvel Cinematic Universe. David Tennant (The Doctor in Seasons 2-4) played Kilgrave in Jessica Jones (2015), Christopher Eccleston (The Doctor in Season 1) played Malekith in Thor: The Dark World (2013), Jenna Coleman (who played Oswin and then Clara beginning in Season 7) played Connie in Captain America: The First Avenger (2011), and Karen Gillan (who played a soothsayer and then Amy Pond beginning in Season 5) played Nebula in Guardians of the Galaxy (2014), Toby Jones, (The Dream Lord in Amy's Choice (2010)) was Dr. Arnim Zola beginning in Captain America: The First Avenger (2011). David Bradley, (Solomon on Dinosaurs on a Spaceship (2012)) played the Tower Keeper in Captain America: The First Avenger (2011).