Scripts and tools that are not allowed within the rules of Travian could be considered cheats. There are several tools out there, some are easy to get banned for if you use and some are not. The most well known types of scripts for Travian are probably the greasemonkey scripts. I’ve written more about greasemonkey in another post here. Use all of the tools and scripts I mention here at your own risk.
There are no cheat codes to Travian, that would kinda mess up the whole game, it is a online multiplayer browser game after all, and having something like that would just ruin the game completely. The various tools available are just made to make the more automatic and less time consuming.
There are really two types of such scripts and tools out there. The first type do in some way give you a better overview of the game, as in Travian maps, overview of alliances and such. The other type aim more at automating things, to different degrees, and enables you to do well in the game without spending that much time playing. Take a look at the other articles here, and hopefully you’ll find something usefull.