Identify the Eeveelutions
Python 2, 77 76 bytes



lambda s:'VFULJSGEalmeoylspaballaporrftvc'[hash(s)%3695%8::8]+'reon'[s&lt;'V':]


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In Python 2, the hash function consistently (across runs and also on different platforms) converts any immutable value into a 64-bit integer. By taking that integer first mod 3695, then mod 8, we get an integer 0&lt;=i&lt;8 (3695 was found by brute force checking all possible values upto 10000).

A common trick is used to encode a list of same-size strings into a single string and then using slicing via [i::8]to extract the strings without using .split or similar strategy. Only two options are not of length 4: Esp and Vapor. The former is handled by making it the last of the 8 strings encoded; and Vapor is handled using the final slicing 'reon'[s&lt;'V':].