It really depended. I'm going to talk about China, because I'm like the Jon Snow of European urban history.

In China, if you were literate, there were certainly vernacular novels and books that would have been consumable - even to the partially literate. High/full literacy even in late imperial China was exceedingly rare, especially for a country as large as China, but there were definitely varying levels of literacy and you didn't need to have the vast, expansive knowledge of literary Chinese a classically educated man of letters would have had to read a simple book. Feng Menglong published his anthologies of vernacular works during the early 17th century, and these pieces for example, would have been accessible to merchants and the like, along with many other works of vernacular Chinese by a variety of other authors, such as MuDan Ting. There were other books intended for the general population as well. Almanacs and “special use books” were popular genres, like texts on traditional Chinese herbal medicine. The almanacs of the period were also sort of general guides which would encompass things ranging from crop planting cycles to geomantic principles. Non-academic encyclopedias were also published. Wen Zhenheng wrote a rather comprehensive encyclopedia on how best to decorate your home, and how to adhere to the 'literati' aesthetic best, and his Treatise on Superfluous Things would have been designed specifically for more ordinary people; as a matter of fact, members of the actual elite would have frowned upon such a work as it was a rather vulgar thing to do, explain how to decorate your house to a gentleman. After all, what gentleman doesn't already have refined tastes in interior design?

In the Chinese south, there was an extremely vibrant culture of book publishing and creation, and these printing boutiques would have churned out large quantities of common-consumption books, ranging from the upright classics, to almanacs and obscene fiction works for the common folk to enjoy. If you are interested, I highly recommend you check out Printing and Book Culture in Late Imperial China.

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Edit: If desired, I can pull some specific examples of these sort of 'vulgar' vernacular texts.

As for Europe (mostly France and England, but it's more or less the same in Italy, Spain and the United Provinces), we know what most people had to read thank to inventories after the death of someone, and various notary acts regarding heritage.

The most common book listed in private library is, without surprise, the Bible. But there was also a lot of "technical book", meaning books about various occupations and technique (printing, smithing...) and "world knowledge" books (Atlas, herbarium...). Spiritual and philosophical litterature is also very common.

Fiction is not very represented in middle classe household. Among the bourgeoisie (the majority of the public for printed books), while fiction is not rare, and the majority of inventories show at least one or two plays or novel, it is not the main focus. Theater is by far the more frequent type of fiction that pops up. In upper classes, however, as the number of book owned by the person increase, so does the number of novels and plays.

If you are interested, there is a few chapters about household and the diffusion of printed work in the Cambridge History of science, wich are easy and quick to read. I can't really recommande you morespecific books on the subject...Unless you speak French. Being french myself, most of my sources are french book, rarely published in english.