Let’s say we have

type ENUM('fish','mammal','bird')

An alternative is

type VARCHAR(20)  COMENT "fish, bird, etc"

This is quite open-ended in that new types are trivially added.

Comparison, and whether better or worse than ENUM:

• (same) INSERT: simply provide the string
• (worse?) On INSERT a typo will go unnoticed
• (same) SELECT: the actual string is returned
• (worse) A lot more space is consumed