These unusual stickers are sometimes thought to have been given away with "The Beano" or "The Dandy" newspaper, because they are plain backed and they say (c) D.C. THOMPSON & Co., Ltd., 1991 on each one. However this is simply the licensing credit for using the copyright image which belongs to D.C. Thomson.
They were actually issued with a cheese substitute which is not named apart from on the application form where it is called just "the delicious alternative to cheese spread". Flora is still active in the vegan cheese scene, and also make "plant b+tter".
These stickers seem to have been designed for the American market, because the set includes baseball, basketball, and American football - but maybe they were paying tribute to the fact that when the paper started it was known as The Beano Comic, most of its content being American style comic-strip cartoons. However the other sports are universal, bicycling, football, and roller skating, albeit in "the old style" with four wheel skates rather than the "inline" fashion of the moment with the wheels in a long line.
All the cards feature Dennis the Menace and Gnasher, and several of the cards also feature a character called Walter, who was first introduced in 1953, two years after Dennis and Gnasher had made their first appearances.
The cover of the first edition was in full colour, and it was published on July 30, 1938. The original first edition of the magazine is scarce and expensive, so there are fakes, and there are licensed reproductions. You can find out how to spot these, and have a look at the cover of issue number one at Beano.com/no-1 - and -do look at that whole site as it combines the new and the vintage into a whirlwind of glorious fun.
And is there anyone out there still has their original whoopee mask?