I recently started watching Arrow and had to then go back to see what I had missed in seasons 1 & 2. There are many great easter eggs for the casual DC fan and some you have to look a little closer and be truly devoted to all things DC. Here I'll list my favorite hidden gems both obvious and deeply hidden.
Originally the city defended by Dick Greyson a.k.a. Nightwing, in Arrow it is a oft mentioned and (this is my personal speculation) decaying district within Starling City. Several key members of Team Arrow end up in Blüdhaven. Ollie even uses it as his excuse for why he was missing after his duel with Ra's Al Ghul when talking to Thea.
2. Garfield Lynns
Garfield Lynns is the original Firefly who is a common Batman rogue. In the comics he's an out of luck visual effects guy, but with a little bit of retooling he became a foe for Ollie. In the TV version Lynns is a former firefighter who was presumed dead in a dangerous fire two years prior. The Firefly nickname comes from the tattoo shared by the members of his former fire house.
3. Barton Mathis
Another Batman villain that was... borrowed from the Bat's rogues gallery. Again minor retooling of the back-story allows him to be Ollie's problem.
4. Sebastian Blood
Sebastian Blood is a common foe of the Teen Titans but again is re-purposed for Arrow. My favorite thing about the use of Brother Blood is the vague use of his actual origin story. In order to become the head of the Church of Blood he would have had to kill his father. The first Brother Blood the Titans faced was Sebastian Blood VIII. The Arrow version also killed his father. What is awesome, and the true easter egg in all of this comes in S2 Ep. 11 "Blind Spot". As Slade Wilson (Deathstroke) shows Blood the file regarding his fathers murder you see that his father's name was "Sebastian Sangre". Arrow producers all but hid the coolest tidbit in a 5 second scene. Sangre is the Spanish word for blood. So literally in order to seize power for himself Brother Blood killed his father who was also named Sebastian Blood.
So what do you think? Are these good Easter eggs?