By rearranging the letters of the word "Spring" I have listed 37 words below (excluding the word Spring) that you are able to make using each letter from the word once.
Let me know in the comments section below if you know any more that I have missed.
1 Letter Words
2 Letter Words
3 Letter Words
4 Letter Words
5 Letter Words
For a list of how many words you can make out of the word Summer click here
For a list of how many words you can make out of the word Autumn click here
For a list of how many words you can make out of the word Winter click here