2) Yoda
In a weird way, Gollum and Yoda are like two sides of the same coin – both are small odd-looking creatures with strange ways of speaking who tag along with the hero in the second instalment of a series. Obviously, Yoda is the far less villainous and more loveable one, though.
Likewise, as opposed to Gollum’s high-tech realization, Yoda is at his best when portrayed as an old-fashioned puppet, where Frank Oz’s voice work and skilled puppetry from all those years with The Muppets can shine through. Possibly the key to Yoda’s success is how he could have easily have been a bumbling kid-friendly sidekick (Jar Jar, anyone?) but instead is the wisest character in the universe. He might be overused in the prequels – but even then he gets to take part in some awesome lightsaber battles.
Second best sequel character ever, he is.