There are no officially adopted text-representations (for IPv4), only binary ones. In other words: there are simultaneously infinitely more possibilities and exactly zero.

For the most part, applications tend to punt the job of interpreting such text address representations to the IP stack (usually embedded in the OS kernel). These vary in what they'll accept by implementation and version, but they tend to be extremely good at interpreting whatever arbitrary nonsense people have historically been likely to try. As a result, there are surprisingly few application-level libraries which even attempt to deal with that mess.