cuneiform isnt even that weird,
check out the multiocular O ꙮ
this was only used once in a single cyrillic manuscript to spell "many-eyed seraphim"

𓂸 𓂹 𓂺 there are hieroglyphs too, and these appear often enough to be included.

Yeah, most dead scripts have Unicode, specifically because how the hell would you write academic papers about them in this day and age otherwise? Even old Irish Ogham:

ᚅᚖᚙᚗ

The line is a convention, because ogham was originally written on the corner of a stone stela.

For anyone else stumbling about this revelation: It very well wouldn't be Unicode otherwise now, would it?

There's a reason linguists and computer scientists sometimes get mental breakdowns over emoji because the know that those same emoji were on the same agenda taking up actual time as discussions about which ancient language or newly discovered grapheme/symbol/lexicogram/whatever should be added first/next. (Not saying emoji aren't also tremendously important/good/what ever additions!!)