I decided to do an article analyzing repetition within LEGO themes. It started out with a desire to do Adventurers while playing the crappy Dino game on LEGO.com.
First up, Adventurers, LEGO's classic exploration theme. Introduced in 1998, this theme had four incarnations: Egypt, Amazon, Dino Island, and Orient Expedition. The first two and the last one explored real settings but contained mystical beings and magic. The third was a Dino Hunter/Nature Protector-type theme, with the villains trying to capture dinosaurs and the Adventurers rescuing them. The theme also had cameos in LEGO Island 2, LEGO Racers, LEGO Racers 2, Soccer Mania, and the LEGO Island Interactive Comics. The theme was centered around three main heroes - Johnny Thunder, Pippin Read, and Dr. Kilroy, who went by other names at various times. Assisting them were a number of people, including Harry Cain and Mike (Harry Cain also has other names). The villain lineup changed - or at least the names changed. Excepting the Amazon subtheme, every Adventurers subtheme had an incarnation of Sam Sinister, a treasure hunter in the vein of Belloq (more on him later). The theme was set in a World War II era, roughly, with biplanes, balloons, and zeppelins all over the place. Basically, it was Indiana Jones, but without all the money going to Lucas and Spielberg. It was a great theme with a lot of backstory and some fantastic sets.
What themes have been, to some degree, in the same vein as adventurers?
And, of course, Indiana Jones.
The main similarities between the first three and Adventurers is, obviously the dinosaurs. That's the full extent of similarities between Dino Attack and Adventurers, and to a lesser extent Dinosaurs and Dino Island. Dino is basically Jurassic Park, and the dinosaur trapping aspect brings it closer to Dino Island, except that this time the Dinosaurs are being trapped to protect people instead of for display, so the good guys are doing the trapping (and the bad guys are Dinosaurs). The colors in these three themes, are quite different than Adventurers.
Pharaoh's Quest is a lot closer - in fact, you could say that it's a direct descendant of Adventurers, particularly Adventurers Egypt. In my opinion, it is the single best theme we have had in years, possibly since BIONICLE, and one of the, if not the, best designed and colored themes ever. The vehicles are more or less the same as the type that come in Adventurers, just more modern, and the landmarks are similar as well - the only difference is that the "adventurers" are fighting mummies instead of collectors - and it works, because if I'm getting Anubis Guard, I couldn't care less about what the story is - that minifigure is one of the most beautiful things you can get.
Indiana Jones need not even be explained - Adventurers was obviously non-licensed Indiana Jones. The Indiana Jones theme is my favorite license, particularly for the games.
This was originally Aquazone, but there weren't enough similarities with other themes to use it properly. Divers was a Town subtheme with large boats, submarines, and a lot of sea life. The divers hunted for treasure. I don't know much else about it.
Alpha Team: Mission Deep Sea was the second incarnation of Alpha Team. It didn't have the exploration elements of Divers, but it did have the underwater vehicles. The style was different, but the vehicles were mostly submarines (as is to be expected). However, the sea creatures were giant mutated monsters and not merely dangerous beasts. The themes are pretty different, they just both happen to be underwater.
I'm not too clear on this story, so correct me if I'm wrong. Aqua Raiders is divers with an enemy. In Aqua Raiders, the previously peaceful sea creatures are now giant beasts, like in Alpha Team: Mission Deep Sea, who for some reason protect treasure on the sea floor. The colors of the Raiders' vehicles come straight from Divers. The themes are quite similar.
Atlantis is very similar to Aqua Raiders, and therefore shares some similarities with Divers. In it, explorers are hunting for the lost city of Atlantis and fight against sea creatures. I'm not sure what the last year of the theme was about, but they fought little sea creatures there.
Alpha Team - the first LEGO Agent-type theme. The LEGO sets were preceded by a game in which you set up a sequence of events for any number of spies to complete in order to push a button - in plain sight of the villain, because why shoot your enemies when you can let them take down your factory? The series revolved around Ogel's orbs. His first set of orbs turned minifigures into zombie servants. The second ones, far more awesomely, turned sea creatures into mutant servants. The last one just froze stuff.
Agents is similar to Alpha Team in that it's a team of secret agents fighting against evil villains planning world domination. The main difference here is the plural - villains. Alpha Team had one villain, Ogel, with a number of servants. Agents had tons, each with a different feature. The theme had very different vehicles from Alpha Team but shared some overall similarities.
Divers is explained above, as is Aqua Raiders.
Rock Raiders is miners mining for energy crystals on a distant planet and being stopped by Rock Monsters who eat the crystals. The theme is awesome, even if the base is poorly designed. The fact that the theme has three books and one of TLG's best video games ever means that the theme has quite a bit of storyline behind it. The Rock Monsters are also awesome, but there are no official Ice Monsters or Lava Monsters, although prototype Ice Monsters are white, so if you get ahold of one of those, call me.
Power Miners is miners mining for energy crystals on their own planet and having to deal with Rock Monsters who eat the crystals. See the difference? It boils down to this: the Power Miners vehicles, although well designed, have really bad color schemes. Instead of awesome dark colors, they use stuff like lime green and orange - which are not necessarily bad colors, but which simply can't capture the coolness of what Rock Raiders had. Oh, and the Rock Monsters are, for the most part, small and silly, which means that they're more of a joke than an enemy. The theme is VERY similar to Rock Raiders.
Western and Lone Ranger
Western is set in the Wild West, as is Lone Ranger. I'm tired at this point. So yeah, I'm done. I didn't bother to proofread this. When you find mistakes, tell me and I'll fix them.