Didn't everyone read the cereal packet? I mean, it was Right There...
Reader's Digest here too, and Punch (as well as all the cartoons there was Let's Parler Franglais and Freaky Fables, and the Caption Competition won more often than not by C Thompson of Glasgow).
The Friendship Book by Francis Gay, and (not quite as good) the Fireside Book of David Hope. Little purple annuals at my grandmother's house. Among other things the Friendship Book was where I first encountered that quote about Young People Today from Plato.
My sisters and I had a phase of reading Barbara Cartland, which had a weird Venn Diagram relationship with Mills&Boon. Such a terrible attitude to instil in young women! Such a... sickening yet... twee... way of talking... about sex! Such a banal writing structure (single-sentence paragraphs)! Such intense detailed historical research!
The dictionary. Never intentionally. Normally after looking something up for a crossword, or a game of Scrabble.
The New Book of Knowledge, a set of children's encyclopaedias from the 1930s. And their companion the Children's Treasure House.
For a while, the hatch-match-despatch and the classifieds in the local paper.
There was the Property Guide as well, but that's normal. (Still remember the fantastic 10-bedroom several-acre property that was the most expensive one I'd ever seen. £100k.)