CommutatorOrder[exp] orders any FCCommutator and FCAntiCommutator lexicographically.
CommutatorOrder[exp]
FCCommutator
FCAntiCommutator
Overview, FCCommutator, FCAntiCommutator.
FCCommutator[a, b] + FCCommutator[b, a] CommutatorOrder[%]
[a,b]+[b,a]
0