Do any published adventures contain spells a wizard can copy that aren't written in a spellbook?

Question

A wizard can copy a spell they find into their spellbook. This is described in the "Your Spellbook" section of the Wizard's class features:

When you find a wizard spell of 1st level or higher, you can add it to your spellbook if it is of a spell level you can prepare and if you can spare the time to decipher and copy it.

Notably, it does not say "when you find a wizard spell in a spellbook". Are there any instances in published adventures where a wizard can copy a spell from something other than a spellbook?

I'm obviously not concerned about spell scrolls here. I'm looking for something like a spell written on a wall or stone tablet, or other surface that does not require a check like a spell scroll does.

This Q&A firmly establishes that the wizard can copy their spells from any written source, but I am not aware of any published examples of this outside of found spellbooks.

Answer 1

There are a few examples.

From Storm King's Thunder

There is a specific room in one of the major locations which has the following:

Chapter 10 says, in Room 25 - Library (p. 212):

Five rocks have the following wizard spells inscribed on them: antimagic field, conjure elemental, fabricate, legend lore, and stone shape. The rocks function like pages of a spellbook, but each weighs 600 pounds. A character who has a spellbook can record these spells in it.

These are not spellbooks, but can provide spells for wizards to copy.

...and there are a few books that aren't strictly spellbooks but do contain wizard spells:

From Out of the Abyss

In one of the major locations, an important NPC has the following item:

Chapter 4 says, in the Treasure section under "Finding Droki" (p. 69):

Pages of lizard-skin parchment held together between two leather covers from two different books. The pages are full of mad scribbles and arcane formulas, but a character proficient in Intelligence (Arcana) can study them for 1 hour to discover that they constitute a spellbook containing the Tenser’s floating disk and feign death spells.

This is not quite a typical spellbook but provides a couple spells in a manner similar to one.

From Icewind Dale: Rime of the Frostmaiden

There is a book found in a major location:

Chapter 5, in Room G22 - Chamber of the Codicil, contains The Codicil of White, a magic book whose description appears in "Appendix D: Magic" (p. 317):

The codicil was written by followers of Auril as a primer on her worship. The first page is a title page with the snowflake symbol of Auril on it. The remaining pages describe various priestly rituals and ceremonies in chilling detail. Nestled among these descriptions is a spell that wizards can learn (frost fingers, described later in this appendix) [...]

While it is a book, it is explicitly not a spellbook, simply containing a spell that wizards can transcribe.

From Dungeon of The Mad Mage

In addition to those above, there is a stone statue with a stone likeness of a spellbook that a spell can be copied from:

On level 7, in the courtyard of Maddgoth's Castle (p. 102)

Statue. In the center of this open-air courtyard, surrounded by gardens of glittering, pebble-sized crystals, stands a 9-foot-tall statue of a plump human wizard (...) reading from a spellbook. (...) Carved into the pages of its open spellbook is the Mordenkainen's Sword spell. A wizard can take a rubbing of the spell and copy it into a spellbook.