Now I know that I am fighting a losing battle, but it is incorrect to talk about these probability diagrams as pictures of orbitals. However this terminology is widespread in all freshman chemistry books and even in most physical chemistry books. So I will use the terminology also even though it makes me cringe. Now let's return to a discussion of the quantum numbers. After f we just follow the alphabet without repeading any letters.
Answer is at the bottom of the page.
Similarly for other combinations of n and l values. It is the spin quantum number. A classical charged particle which is spinning would generate such a magnetic field, but since the electron is not a classical particle, we don't know what it is doing. However we do refer to this as the spin quantum number. This site will give you an illustration of various quantum mechanical orbitals .