Recently a group of baseball stickers came up for auction on ebay that caught my eye:
I believe these were put out by Kellogg's in the late 1970s as they are very similar to the 1978 Kellogg's Football Stickers that were available in packages of Pop-Tarts:

Unfortunately however, whereas the Football stickers have information on the back with the Kellogg's logo

the baseball stickers have blank backs.
In looking around to see if I could find any other examples of these stickers, I did find a few examples of stickers still in the packaging that they would have originally come in
as well as a few examples of some that had been opened
The seller identifies these individual stickers as 1978 Kellogg's stickers based on the similarity to the football stickers, but indicates Kellogg's is not mentioned on the packaging or on the sticker.
The stickers were packaged individually, so the stickers that were recently up for auction look like parts of a strip that was cut into sections of two stickers.
I remember getting some of these stickers as a kid, and still have the A's sticker stuck on the trunk that is the "Original" Fleer Sticker Project:
That is why I was so glad to come across this group of stickers - I have always thought that the A's sticker had come from a breakfast item, and now I think I have the proof:


























