The .243 Winchester is also a necked-down .308 Winchester.
I believe the .270 Winchester and the 25-06 Remington are necked-down .30-06 Springfield.
Going in the other direction, the .35 Whelen and .338-06 A-Square are necked-up .30-06 cases.
I'm sure there are others, but these are the ones that come to mind easily...
.30-06 Springfield: 100 yrs + and still going strong