The Beano and Dandy Comic Libraries were digest-sized spin-offs of the two full-size comics, which were published at the rate of four per month (two Beanos and two Dandys) from 1982 to 1997. Each one was 64 pages long and told a single, long-form story starring one or more of D. C. Thomson's main characters, often pairing them up in unusual crossovers. In 1997 the Comic Libraries were supplanted by the Fun-Size Beano and Fun-Size Dandy, which were extremely similar but featured two or three stories per issue plus a selection of other features such as puzzle pages and cut-out-and-keep guides; they continued in this format until 2010, slowly featuring more and more reprinted material, until being discontinued due to low sales.
In the days of the Comic Libraries, however, there were two spin-off ranges: the Beano Puzzle Books, which are hopefully self-explanatory, and the Dandy Cartoon Books.
The Cartoon Books were the same format as the Libraries, but with a different cartoon, usually a single frame, on each page (with the occasional two-pager); despite all being published under the Dandy banner, they featured a wide mix of characters from across DCT's humour comics, often featuring characters which had been defunct for years. They were published monthly for some seven years.
It's worth emphasising that the team putting these together would have had to come up with sixty or so different gags every month for all that time. Given that, the hit rate was surprisingly high, and it seems only fair to provide you with some of my favourites before moving on to the other side of things: