The 3-transposition groups that act on vertex operator algebras in the way described by Miyamoto in [Mi] are classified under the assumption that the group is centerfree and the VOA carries a positive-definite invariant Hermitian form.
Atsushi MATSUO. "3-transposition groups of symplectic type and vertex operator algebras." J. Math. Soc. Japan 57 (3) 639 - 649, July, 2005. https://doi.org/10.2969/jmsj/1158241926