I believe you meant 300.4(G)...
Assuming the OP is referencing conduit bushings, also 300.5(H), 300.16(B), 334.15(C), 342.46, 344.46, 352.46, 352.46, 354.46, and 355.46. When not limited to conduit terminations, there are many other sections which require the use of an insulating bushing.