Check out the Wikipedia article https://en.wikipedia.org/wiki/Nothing_up_my_sleeve_number for some examples:

ARIA uses 1/π (indeed, why not pi?)

MD5 uses sin(n) (why not cos(n) or sqrt(n)?)

SHA-1 and SHA-2 use square roots and cube roots of small primes (why not sin(n) or pi?)

DFC uses e.

NewDES uses the United States Declaration of Independence.

RC5 uses both e and the golden ratio.

BLAKE uses "a table of 16 constant words which are the leading 512 or 1024 bits of the fractional part of π". (Here you see how things like bit or byte order can give you more choices.)