In 1982, I wrote a computer program (later known as Ars Magna TM) which used a dictionary to produce all possible anagrams for a phrase entered by the user. At about the same time, Jim Woods of the NASA/Ames Research Center in California wrote a similar program. Perhaps there are more, though I haven't heard of them.
"Computer Anagrams: Not Much Progress,"
Word Ways: Vol. 22
, Article 16.
Available at: https://digitalcommons.butler.edu/wordways/vol22/iss2/16