There are various Unicode blocks dedicated to symbols. There are cartography symbols, domino tiles, alchemical symbols... There is even a block for "legacy computing".

https://en.wikipedia.org/wiki/Unicode_block#List_of_blocks

Text is symbols.

And Unicode in particular has loads of non-letter symbols in it. It's only natural, given that a lot of these often show up in line with regular letters. Think of various paper documents you read, like instruction manuals, which make heavy use of non-letter glyphs in text.

There's plenty symbols in it. For instance:

https://www.fileformat.info/info/unicode/block/miscellaneous...