Besides Death in the books of Sir Terence David John Pratchett, OBE (10 Doctors and a Professor omitted), there are lots of precedents for special font or alignment for various usages.
In contrast to some modern prints (see below), the 42-line Gutenberg Bible in Latin of 1454 (part 1) (part 2) uses the same font for everything and no special printed lettering. The first letter of chapters also is either red or blue and often with some artistic scrollwork, all added later. The red annotations, chapter headers and other were added by hand later, using a separate document for the scribe. Note that besides those small annotations, the commentary is fully absent in this print, a break from many earlier, handwritten bibles (see below).
According to Christopher De Hamel: Eine Geschichte der Bibel, Berlin 2002, handwritten, commented bibles usually used red ink or red underlines for the actual bible-text and only black ink for the commentary, which was often an explanation of the archaic Latin. Another accepted version to denote the bible text was to put a special zig-zag like mark at the side of the quotes from the word of god or to put the bible quote in font of double the height while the commentary surrounded this. Some excerpts can be seen on the author's german page. So technically one could say "the word of god" (as in the bible text itself) had a special font in those 13th-century bibles.
Red Letter Editions only came up in 1899, and is especially popular with the King James Version in the US.
Douglas Noel Adams, also a writer of comedy, had one single notion of a god to the world in So long thanks for all the fish. Chapter 40 showed us this ingenious way to get a message from God to the people: He has the almost blind Marvin see the burning, house-sized capital letters through a telescope... and then spells it letter for letter to the reader. He never spells it out.
first letter was a “w”, the second an “e”. Then there was a gap. An “a”
followed, then a “p”, an “o” and an “l”. Marvin paused for a rest. After a few moments they resumed and let him see the “o”, the “g”, the “i”,
the “s” and the “e”. The next two words were “for” and “the”. The last one was a long one, and Marvin needed another rest before he could tackle it. It started with an “i”, then “n” then a “c”. Next came an “o” and an “n”,
followed by a “v”, an “e”, another “n” and an “i”. After a final pause, Marvin gathered his strength for the last stretch.
He read the “e”, the “n”, the “c” and at last the final “e”, and staggered back
into their arms.
Stephen King sometimes uses special alignment to make something noteworthy. For example, a center alignment has been used to demark what was written on pieces of paper in IT (especially in chapter "Part Four, July of 1958: Chapter 16, Eddie's Big Break"), italic was used heavily for thoughts of the current protagonist.
Also by Stephen King, The Stand. We can find the following in Chapter 53 (at least in my print): Once more, center alignment is used for a couple of papers, right alignment and italics for signatures, and as a special use he uses CAPITALS to declare what a note of paper (written in wonky capital letters) to Nadine said while the normal text - interspaced to the note - is used for the actions and what was to be seen at the same time. Again left-aligned italics are used throughout the book for thoughts.
Bram Stoker, Dracula. As an example of a book written in letters and diary entries, typography is used a lot. After a center-aligned, capital font header denoting the "source material", there are easily 2 types of setups used:
- In letters, alignment is used to denote date and address (right-aligned italics), the addressee (left-aligned italics), body (column alignment) and sender (right-aligned italics) of the letters.
- At times some parts in the body are put into italics, denoting a special style of writing
- Diary entries are started with the italic date and sometimes time.
- At times indented italics on a separate line are used: Johnathan Harker's entry for the 16th May has a Hamlet quote in this way. His 4th May entry has a quote from Burger's 'Leonore'
- A couple of pieces of news and reports have another, slightly different typography.