Superscripts and Subscripts characters supported by the Source Serif Pro font

Character	Image
SUPERSCRIPT ZERO (U+2070)
SUPERSCRIPT LATIN SMALL LETTER I (U+2071)
SUPERSCRIPT FOUR (U+2074)
SUPERSCRIPT FIVE (U+2075)
SUPERSCRIPT SIX (U+2076)
SUPERSCRIPT SEVEN (U+2077)
SUPERSCRIPT EIGHT (U+2078)
SUPERSCRIPT NINE (U+2079)
SUPERSCRIPT LEFT PARENTHESIS (U+207D)
SUPERSCRIPT RIGHT PARENTHESIS (U+207E)
SUPERSCRIPT LATIN SMALL LETTER N (U+207F)
SUBSCRIPT ZERO (U+2080)
SUBSCRIPT ONE (U+2081)
SUBSCRIPT TWO (U+2082)
SUBSCRIPT THREE (U+2083)
SUBSCRIPT FOUR (U+2084)
SUBSCRIPT FIVE (U+2085)
SUBSCRIPT SIX (U+2086)
SUBSCRIPT SEVEN (U+2087)
SUBSCRIPT EIGHT (U+2088)
SUBSCRIPT NINE (U+2089)
SUBSCRIPT LEFT PARENTHESIS (U+208D)
SUBSCRIPT RIGHT PARENTHESIS (U+208E)

Count: 23

Character
SUPERSCRIPT PLUS SIGN (U+207A)
SUPERSCRIPT MINUS (U+207B)
SUPERSCRIPT EQUALS SIGN (U+207C)
SUBSCRIPT PLUS SIGN (U+208A)
SUBSCRIPT MINUS (U+208B)
SUBSCRIPT EQUALS SIGN (U+208C)
LATIN SUBSCRIPT SMALL LETTER A (U+2090)
LATIN SUBSCRIPT SMALL LETTER E (U+2091)
LATIN SUBSCRIPT SMALL LETTER O (U+2092)
LATIN SUBSCRIPT SMALL LETTER X (U+2093)
LATIN SUBSCRIPT SMALL LETTER SCHWA (U+2094)
LATIN SUBSCRIPT SMALL LETTER H (U+2095)
LATIN SUBSCRIPT SMALL LETTER K (U+2096)
LATIN SUBSCRIPT SMALL LETTER L (U+2097)
LATIN SUBSCRIPT SMALL LETTER M (U+2098)
LATIN SUBSCRIPT SMALL LETTER N (U+2099)
LATIN SUBSCRIPT SMALL LETTER P (U+209A)
LATIN SUBSCRIPT SMALL LETTER S (U+209B)
LATIN SUBSCRIPT SMALL LETTER T (U+209C)

Count: 19