Can you recognise them all?

I just stumbled upon (and when I say stumbleupon what I’m really meaning is 9gag) this picture with a whole bunch of TV-Show’s main charachters all gathered together in one room:

I was only able to spot 15 of them, and my favourite is the one in the down-right corner sat on the couch.

How many of them can you recognize?

Anna Rettberg, the author of this magnificent drawing, directly provide a complete description. Anyway for the lazy ones I’ve hidden the solution down below, click on show source to see it!

SOLUTION:

• Back row, left to right:
  Dwight (The Office), Caprica 6 (Battlestar Galactica), Dr. House (House), JD (Scrubs), Tobias (Arrested Development), Liz Lemon (30 Rock), River (Firefly), Jack and Vincent (LOST), The 11th Doctor (Doctor Who), Walter (Breaking Bad), Sheriff (Walking Dead)
• Middle row:
  Buffy (Buffy the Vampire Slayer), Bill (True Blood), Jeff (Community), Quinn or really any other cheerleader from (Glee) and honestly could be Claire from (Heroes) if you'd prefer, Barney (How I Met Your Mother), Don Draper (Mad Men), Dexter (Dexter), Sherlock Holmes (Sherlock)
• Bottom row:
  Sheldon (Big Bang Theory), Spock (Star Trek:TOS), Chuck (Chuck), Sydney Bristow (Alias)
• Window:
  TARDIS (Doctor Who), USS Enterprise (Star Trek), Galactica (Battlestar Galactica), Serenity (Firefly)
• Also, the dog is sorta supposed to look like the dog from Frasier, and the cat is sorta like the one from Sabrina (I've never watched either show, so I wasn't super particular about getting them right. Just wanted a few animals in it!)