There are so many answers to this question, it just depends on how you interpret the word "series".

These maybe 'themes' more than series but off the top of my head

Comic Book/Cartoon - Spiderman, Superman, Incredile Hulk, Judge Dredd, Popeye, Simpsons, Family Guy, Shrek, Flintstones, Batman........

Horror - Dracula, Bram Stokers Dracula, Frankenstein, Freddy - A Nightmare On Elm Street, Class of 1812, Bonebusters, Monster Bash, Haunted House........

Movies/Books - BSD, Freddy, JD, Frankenstein, LOTR, Flintstones, Batman x 3, Twister, JP x 2, Apollo 13, Dirty Harry, T2, T3........

Space Travel - Space Shuttle, Pioneer (sort of), Apollo 13, Space Odyssey, Attack from Mars, RFM.......

Sport - No Fear, Champion Pub, Blackwater 100, WH2O, Basketball, WWF......

Adventure/Fantasy - Sorcerer, MM, Centaur, Flash, Fireball x 3...... 

Magic/Circus - CV, TOM, Pinball Magic......

You get the drift anyway, there are so many more that could be added and as you can see, my knowledge of the early machines is very limited.