How would you count a base $> 36$ system? When I am counting in a base greater than ten, I can use the letters of the alphabet.  What do I use when I run out of those?
What comes after $z$?:
$0, 1, 2, 3,\ldots, 9, a, b, c, d,\ldots, x, y, z$ (?)
And how would I find it?

+, -, /, { ,], ä, ö, ü, ß, ă, î, ț, ﺞ, 덖, 哶, ...
There are millions of characters you could use. There are standards mostly used for base $64$  or base $32$ but I'd say that it's mostly up to you what you choose.
