There are a total of 151 Pokemon in Red, Green, Blue, and Yellow. However, you will not be able to capture all of them unless you trade with the other versions. All 151 are available with just Red and Blue, but if you’re playing Yellow you will need to trade to both Red and Blue to get some of the version exclusive Pokemon.
The table lists all 151 Pokemon, their types, where they can be found in Kanto, and in which English versions. If the space is blank, they cannot be found in the wild. You may be able to evolve a previous evolution to get it. Furthermore, the majority of water Pokemon are found with the Super Rod throughout Kanto.