Sunday mornings were always like "mini-saturdays" here. One (and only one) local affiliate showed cartoons (I'm 90% certain it was the ABC one). They didn't have any religous crap, but it was second-run kind of stuff. Rocky & bullwinkle, deputy dawg/mighty mouse, the porky pig show (which mostly consisted of 1930s warner bros toons), funny company (an early edutainment toon form the 60s), and I think a few others of similar ilk. A second reason why I considered sunday mornings as mini-saturdays was because the toons were only on for a couple hours, then they switched to live action shows, which included chips, 8 is enough, fire, emergency, and the waltons.
Years later, that channel stopped their sunday morning content, but by that time I had cable & the USA cartoon express. Cartoon express fell somewhere between saturday & the older sunday both in content & duration, only extending till noon (effectively ending at 11 later on, when the just had totally lameass homebrew shows for the last hour) whereas saturday toons ran till 1pm or sometimes even later.
It's funny, a while ago I was thinking about making a thread about this same basic topic.