I was too afraid to take this exam when I was testing- for all the reasons mentioned in this thread, and most importantly, I didn't have a lot of preexisting knowledge in the topics, so I would have needed a lot of resources to help me build from scratch.
SINCE THEN, I have stumbled on a few resources / classes that I've passed on to homeschool families who follow my blog- I can't say for sure that you could get exact alignment, but again, this is one where you'd really need to be "well read" in the subject. I'm also posting the notes I have for alternatives to the CLEP humanities exam (Study.com, Shmoop, etc.)
So- when Udemy did their Black Friday sale and everything was $10, I scoured their site for courses that could be part of a humanities course (and others, but since you're looking for humanities). Prices will not be $10 now, so ymmv. But they have a ton of music and art courses. Here are 3 I had bookmarked:
Music Theory Comprehensive Complete! (Levels 1, 2, & 3) (regular price $60)
Music Theory Comprehensive Combined: Part 4, 5, & 6 (regular price $100)
Music Theory Comprehensive Combined: Part 7, 8, & 9 (regular price $100)
Modern States has a Humanities course:
https://modernstates.org/course/humanities-2/
Sayor Academy has an Art Appreciation course:
https://learn.saylor.org/course/view.php?id=360
The Great Courses has a streaming option called The Great Courses Plus, which is like Netflix but for educational content. They have many that would align well with humanities: Understanding Opera, History of European Art, Masterpieces of the Ancient World, How to Look at and Understand Great Art, The World’s Greatest Churches, The Louvre, and Understand Great Music.
DSST: You can earn credit for the DSST Art of the Western World FIRST and then use your knowledge of art toward the art aspect in the CLEP. These would not duplicate credit, you'd get both.
Study.com offers an Intro to Humanities course
Shmoop offers a ton of courses in the humanities category
Sophia offers 2 courses Sophia Visual Communications (3 cr.)
Introduction to Art History (3 cr.)
Ed4Credit Literature (3 cr.) Film Appreciation (3 cr.) $195 per class
Finally, edX has a zillion courses in this category - all free.
https://www.edx.org/