Besides Volo's Guide, do any of the other published sourcebooks have in-universe counterparts?

Question

Volo's Guide to Monsters, published by Wizards of the Coast in 2016, is a monster book, expanding on the monsters available to DMs. The book's namesake, Volo, is a real character in the Forgotten Realms, and his book is mentioned several times in published adventures:

On a success, a character discerns that Volo is honest but might be stretching the truth about how much he can pay. (Currently low on cash, Volo is awaiting royalty payments from Volo’s Guide to Monsters. To make more coin, he began work on a new book, Volo’s Guide to Spirits and Specters. As it happens, his knowledge of spirits mostly concerns the alcoholic variety, and the writing has not been going well.)
-Waterdeep:Dragon Heist

The legendary world traveler is in Port Nyanzaru to deliver signed copies of his new book, Volo’s Guide to Monsters, to the merchant princes (some of whom he knows well, and others he claims to know well), and to promote his latest work. Characters are most likely to encounter Volo in one of the city’s inns or taverns, or in a merchant prince’s villa.
If the characters buy a copy of Volo’s book (50 gp for a durable hardcover edition), they can put it to use. Any time they want to know lore about a particular monster described in the book, give them useful tidbits from Volo’s Guide to Monsters. Do not impart game statistics, since such information would not be available in-world. If this reference is unavailable, use the information in appendix D.
-Tomb of Annihilation

So you can acquire Volo's Guide both in real life, and in game (but no longer on D&D Beyond).

In similar style, many of the other published 5e sourcebook titles are stylized as they would appear within the game world they describe:

• Xanathar's Guide to Everything
• Sword Coast Adventurer's Guide
• Mordenkainen's Tome of Foes
• Mordenkainen's Fiendish Folio Volume 1
• Guildmaster's Guide to Ravnica
• Van Richten's Guide to Ravenloft
• Explorer's Guide to Wildemount
• Wayfinder's Guide to Eberron

Do any of these books have in-universe counterparts like Volo's Guide?

Answer 1

Mordenkainen's Tome of Foes fits this criteria.

The preface to Mordenkainen's Tome of Foes features a message from the arcanaloth Shemeshka the Marauder, who delivered a book called Mordenkainen's Tome of Foes, a book dictated by Mordenkainen and penned by his apprentice Bigby.

Although Mordenkainen's Fiendish Folio Volume 1 is also presented with a preface titled "On Fiends and Folios", suggesting it represents an in-world work by Mordenkainen, it doesn't specifically name it. Van Richten's Guide to Ravenloft is similarly named for earlier 2e books such as Van Richten's Guide to Vampires, which were written in-world.

There are some earlier works in D&D where the name of a sourcebook is also the name of an in-world book, such as:

• The Book of Vile Darkness lent its name to 3e's Book of Vile Darkness and 4e's The Book of Vile Darkness
• The Book of Exalted Deeds was also a 3e book
• The Demonomicon of Iggwilv lent its name to the 4e Demonomicon
• Wakeman's The Illithiad, a book on mind flayers, is referenced in the 2e sourcebook The Illithiad
• Winninger's Guide to the Underdark (mentioned in The Illithiad) is a reference to real sourcebook Drizz't Do'Urden's Guide to the Underdark by Ray Winninger
• Mordenkainen's Magnificent Emporium lends its name to the 4e sourcebook Mordenkainen's Magnificent Emporium
• In the 1983 World of Greyhawk box set, divided into the Guide and the Glossography, the foreword to the Glossography reveals that both books in fact exist within the World of Greyhawk setting
• Volo's Guide to All Things Magical includes a foreword by Elminster of Shadowdale, who complains about the title, but decides the book should be published in Faerun anyway, meaning that a book of that name exists with in the Realms; similarly Volo's Guide to Cormyr et al

Technically, the real world is part of the D&D multiverse, as appearing in Dragon magazine #100's The City Beyond the Gate and Ed Greenwood's Dragon article such as The Wizards Three. In the latter set of articles, it is revealed that Ed Greenwood is literally visited by Elminster, who is the source of most of the information appearing in his sourcebooks. Therefore, technically, all real-world D&D books are part of the D&D multiverse.

Answer 2

Not in printed form

The boring answer is that, as far as I can tell, none of the other Guides have been featured in the adventures published so far by Wizards of the Coast.

The more fun (and maybe less serious) answer is that in non-printed form, potentially all the published works appear in a session of Tomb of Annihilation, DMed by Chris Perkins (the adventure's co-designer, co-managing-editor, and co-story designer) at PAX South 2018. Breaking the 4th wall, the PCs are transported to the Wizards of the Coast Headquarters in Renton, where they in particular see the DMG, PHB, MM, and the Tomb of Annihilation module itself -- and it stands to reason that copies of all the other books can be found there, too.