The Normal type covers most of the Pokémon moves than the rest of the types. Most of them are harmless, or don't do it directly, they affect the Pokémon's characteristics instead. However, the damaging moves are based on standard attacks, like Tackle and Scratch.
Normal-type Pokémon are more varied, with various statistics, growths and evolution methods. They also differ in habitats, they can be found in forests, caves, mountains, cities, etc.
This type is the one with less weaknesses, along with the Electric type. But this type is also the only one that isn't very effective against another one.