What nonstandard ways of denoting that something is the title of a work of literature exist?

Solution 1:

I would use quotation marks for titles when italics are not available at least the first time. This would be preferable to doing nothing at all. For example

I read "The Great Gatsby."

If it is unclear that it is the title of a book, you can refer to it as such in the text in addition to quotation marks. For example:

I read a book titled "The Great Gatsby."

If it is clear on subsequent mentions of the title what it is referring to (which is usually the case), then you could drop the quotation marks and simply just mention the name. For example:

I read two books titled "James and the Giant Peach" and "The Great Gatsby." Then I got out of bed. I tripped on The Great Gatbsy on the way out of my room.

Solution 2:

A nonstandard way would be caps

I read a book titled THE GREAT GATSBY.