Surely SpeedSim is the most popular tool in Ogame. It simulates battles in ogame.
You only need to enter the number of ships, defense and technology (weapon tech, shielding tech, armor tech) on both sides to be able to immediately know the outcome of the battle (can be taken as a combat report). An effective tool for all ogame players! Small capacity, free and download is very easy.
The only downside of SpeedSim is that it is not 100% accurate. It is easy to understand, because ogame also relies heavily on random mode.