Life of Fred is a literature-based math curriculum that covers elementary through college level math. The books are engaging and humorous. (Note: they are written from a Christian perspective, with occasional religious references, which can be skipped when reading aloud.)
Beast Academy is a comic book style math curriculum for elementary age mathematically inclined children. Engaging and fun, and includes challenging problems.
Art of Problem Solving follows Beast Academy and offers curriculum for upper grades aimed at mathematically inclined students.
Miquon is a hands on math curriculum for elementary ages, great for very spacial children.
Key To Series is a great follow up to Miquon for middle grades.
Rays for Today is an elementary curriculum that appeals to the more verbal and sequential children.
Singapore Math is a popular elementary curriculum that lends itself well to self-study.
Math Mammoth is another popular self-study curriculum.
Right Start is an elementary and middle grades curriculum which includes a large hands on component.
Math U See is another hands on approach which covers elementary through high school and includes DVDs with thorough explanations of the material (be aware that MathUSee has extra Bible songs on some of their DVDs).
Khan Academy offers online instructional videos on many math topics for elementary through high school age.
Hands On Equations offers manipulatives, manuals, and apps that help elementary age children develop an understanding of fractions and equations.
Jacob’s Elementary Algebra is a mastery-based high school level math textbook series that uses stories, cartoons, and comic strips, as well as a lot of visual material.