Superscripts and subscripts for some characters are in the U+2070 – U+209C Unicode range:
superscript:
0456789+-=()in
subscript:
0123456789+-=aeoxhklmnpst
There's also:
subscript
j
at U+2C7Csubscript
iruv
at U+1D62–U+1D65superscript
123
you have already found
and so-called "phonetic modifier letters" (which for most purposes look like superscript):
abdegkmoptuv
at U+1D43–U+1D5Bc
at U+1D9Cf
at U+1DA0z
at U+1DBBhjrwy
at U+02B0–U+02B8lsx
at U+02E1–U+02E3.
So, assuming you have a font that supports all those characters and the modifier letters look similar to the superscript letters, you have the following:
superscript: all digits, all lowercase ASCII letters, and some other symbols
subscript: all digits, letters
aehijklmnprstuvx
, and some other symbols