From: Xah Lee on
some collection of math symbols in unicode.

• Math Symbols in Unicode

• Arrows in Unicode

• Matching Brackets in Unicode

these are grouped by the symbol's purpose as much as possible.

i made them because i can't find unicode symbols grouped by purpose

The unicode “plane -> block” structure does not group symbols well,
because the chars are added throughout the decades. Some symbols get
added in one block, but later on related symbols get added elsewhere.
For example, binary relational symbols are scattered in different
unicode blocks. Same for binary operators, or all symbols used for set
theory, etc. Sometimes a symbol has multiple uses in different math
fields, so which block it gets added into unicode is not well defined.

hope it's useful to some one.