My group has tinkered with both the 1936 and 1939 scenarios. We own most of the expansions but as of late our top 3 have been Winter War, US War Plans, and Turkey at War.
Winter War- We use this to make the Molotov-Ribbentrop pact more of a serious question for the Soviet Union and to give Finland a chance while adding pieces to Russia as well.
US War Plans- This one is a new favorite and has more potency with the '39 scenario but does work well with the '36 scenario. We use it mainly to help the US set itself better for the war in the Atlantic with Plans Grey and Indigo. Plan Citron also helps in South America as lately Germany has been successfully aligning Argentina which causes problems.
Turkey at War- Who doesnt love a little added spice to the Mediterranean? The rules are fairly simplistic and Turkey really can become the linchpin for keeping or loosing the Med. If the Allies get it, it will help out France/Free France put the screws to Italy with Britain’s aid. The Axis getting it guarantees Mare Nostrum for Italy and allows for a spring board into the Balkans, Middle East, the Caucasus and Kiev. If the Soviets get it, say goodbye to the Balkans and much of the Middle East. So Turkey can really shake up Europe and the Med so it’s great.
Hope that helps.