Good knowledge / looking on the net,Actually you are thinking of Sugar Smacks maybe …
“Variety pack
In 1960 the variety pack was six individual sized packs. They were two packs of Cornflakes and four others from Rice Krispies, Special K, Frosties, Sugar Ricicles, Sugar Smacks and 30% Bran Flakes.
Sugar Smacks
These were a sweetened puffed wheat breakfast cereal similar to Quaker Sugar Puffs (see below). In the USA they debuted in 1953. They were available in the UK by 1960.”
I had forgotten all about Special K and Bran Flakes, those were both to be avoided unless desperate because it was rumoured they might actually be good for you or give you the shits in the case of Bran Flakes :-)