All of the following are vitamers of Vitamin B6, except:
Vitamers:
The term vitamers represents the chemically similar substances that possess qualitatively similar vitamin activity. 
Some good examples of vitamers are given below:

Retinol, retinal and retinoic acid are vitamers of vitamin A.
Pyridoxine, pyridoxal and pyridoxamine are vitamers of vitamin B6.

Key Concept:
Pyridoxine, pyridoxal and pyridoxamine are vitamers of vitamin B6.
Ref : 1- Textbook of Biochemistry, Satyanarayana
Pyridoxine
Pyridoxone
Pyridoxal
Pyridoxamine