How to find the unicode of the subscript alphabet?

Take a look at the wikipedia article Unicode subscripts and superscripts. It looks like these are spread out across different ranges, and not all characters are available.

Consolidated for cut-and-pasting purposes, the Unicode standard defines complete sub- and super-scripts for numbers and common mathematical symbols ( ⁰ ¹ ² ³ ⁴ ⁵ ⁶ ⁷ ⁸ ⁹ ⁺ ⁻ ⁼ ⁽ ⁾ ₀ ₁ ₂ ₃ ₄ ₅ ₆ ₇ ₈ ₉ ₊ ₋ ₌ ₍ ₎ ), a full superscript Latin lowercase alphabet except q ( ᵃ ᵇ ᶜ ᵈ ᵉ ᶠ ᵍ ʰ ⁱ ʲ ᵏ ˡ ᵐ ⁿ ᵒ ᵖ ʳ ˢ ᵗ ᵘ ᵛ ʷ ˣ ʸ ᶻ ), a limited uppercase Latin alphabet ( ᴬ ᴮ ᴰ ᴱ ᴳ ᴴ ᴵ ᴶ ᴷ ᴸ ᴹ ᴺ ᴼ ᴾ ᴿ ᵀ ᵁ ⱽ ᵂ ), a few subscripted lowercase letters ( ₐ ₑ ₕ ᵢ ⱼ ₖ ₗ ₘ ₙ ₒ ₚ ᵣ ₛ ₜ ᵤ ᵥ ₓ ), and some Greek letters ( ᵅ ᵝ ᵞ ᵟ ᵋ ᶿ ᶥ ᶲ ᵠ ᵡ ᵦ ᵧ ᵨ ᵩ ᵪ ). Note that since these glyphs come from different ranges, they may not be of the same size and position, depending on the typeface.

You can copy the characters from the Wikipedia page mentioned in the other answer. Then in python

characters = '⁰ ¹ ² ³ ⁴ ⁵ ⁶ ⁷ ⁸ ⁹ ⁺ ⁻ ⁼ ⁽ ⁾ ₀ ₁ ₂ ₃ ₄ ₅ ₆ ₇ ₈ ₉ ₊ ₋ ₌ ₍ ₎ ᵃ ᵇ ᶜ ᵈ ᵉ ᶠ ᵍ ʰ ⁱ ʲ ᵏ ˡ ᵐ ⁿ ᵒ ᵖ ʳ ˢ ᵗ ᵘ ᵛ ʷ ˣ ʸ ᶻ ᴬ ᴮ ᴰ ᴱ ᴳ ᴴ ᴵ ᴶ ᴷ ᴸ ᴹ ᴺ ᴼ ᴾ ᴿ ᵀ ᵁ ⱽ ᵂ ₐ ₑ ₕ ᵢ ⱼ ₖ ₗ ₘ ₙ ₒ ₚ ᵣ ₛ ₜ ᵤ ᵥ ₓ ᵅ ᵝ ᵞ ᵟ ᵋ ᶿ ᶥ ᶲ ᵠ ᵡ ᵦ ᵧ ᵨ ᵩ ᵪ'
for c in characters.split():
    print(c + '=' + hex(ord(c)))

⁰=0x2070 ¹=0xb9 ²=0xb2 ³=0xb3 ⁴=0x2074 ⁵=0x2075 ⁶=0x2076 ⁷=0x2077 ⁸=0x2078 ⁹=0x2079 ⁺=0x207a ⁻=0x207b ⁼=0x207c ⁽=0x207d ⁾=0x207e

₀=0x2080 ₁=0x2081 ₂=0x2082 ₃=0x2083 ₄=0x2084 ₅=0x2085 ₆=0x2086 ₇=0x2087 ₈=0x2088 ₉=0x2089 ₊=0x208a ₋=0x208b ₌=0x208c ₍=0x208d ₎=0x208e

ᵃ=0x1d43 ᵇ=0x1d47 ᶜ=0x1d9c ᵈ=0x1d48 ᵉ=0x1d49 ᶠ=0x1da0 ᵍ=0x1d4d ʰ=0x2b0 ⁱ=0x2071 ʲ=0x2b2 ᵏ=0x1d4f ˡ=0x2e1 ᵐ=0x1d50 ⁿ=0x207f ᵒ=0x1d52 ᵖ=0x1d56 ʳ=0x2b3 ˢ=0x2e2 ᵗ=0x1d57 ᵘ=0x1d58 ᵛ=0x1d5b ʷ=0x2b7 ˣ=0x2e3 ʸ=0x2b8 ᶻ=0x1dbb

ᴬ=0x1d2c ᴮ=0x1d2e ᴰ=0x1d30 ᴱ=0x1d31 ᴳ=0x1d33 ᴴ=0x1d34 ᴵ=0x1d35 ᴶ=0x1d36 ᴷ=0x1d37 ᴸ=0x1d38 ᴹ=0x1d39 ᴺ=0x1d3a ᴼ=0x1d3c ᴾ=0x1d3e ᴿ=0x1d3f ᵀ=0x1d40 ᵁ=0x1d41 ⱽ=0x2c7d ᵂ=0x1d42

ₐ=0x2090 ₑ=0x2091 ₕ=0x2095 ᵢ=0x1d62 ⱼ=0x2c7c ₖ=0x2096 ₗ=0x2097 ₘ=0x2098 ₙ=0x2099 ₒ=0x2092 ₚ=0x209a ᵣ=0x1d63 ₛ=0x209b ₜ=0x209c ᵤ=0x1d64 ᵥ=0x1d65 ₓ=0x2093

ᵅ=0x1d45 ᵝ=0x1d5d ᵞ=0x1d5e ᵟ=0x1d5f ᵋ=0x1d4b ᶿ=0x1dbf ᶥ=0x1da5 ᶲ=0x1db2 ᵠ=0x1d60 ᵡ=0x1d61

ᵦ=0x1d66 ᵧ=0x1d67 ᵨ=0x1d68 ᵩ=0x1d69 ᵪ=0x1d6a