° -- i.e. [⇑][^]
¶ --e.g. [Alt Gr][R]
· -- e.g. [Alt Gr][,]
… -- e.g. [Alt Gr][,]
– -- e.g. [Alt Gr][-], though optically ambiguous with -, a candidate for *unary
¬ e.g. [Alt Gr][6], also a great candidate for unary use
now I see they are usable, too, which to me is great news.
Since some time, I began using chars like þ, ø, æ, ŋ, ð, µ, ħ, etc., which, easily accessible on a Linux keyboard, have more than cosmetic utility to me; with find / replace it prevents you from the usual trouble when working – but that with the special chars above is a pleasing discovery. :-)
I ever wondered for the reason that in Haskell function composition is not declared by (°) instead of (.), which (a) interferes with other uses of the period and (b) looks less similar to the actual symbol.
It also reminds me of a very beautiful feature (Emacs) haskell-mode had some years ago; it was able to display special characters in wider characters (maybe using a special Emacs font??) – does anybody know what I am speaking about, too?
Unfortunately, this feature wasn't continued while frankly, "←" as in recent use to me slightly hurts the eye a little everywhere it's seen in code (sorry, "←"... ;-), while back then, in Emacs there where BEAUTIFUL arrows in double width and gorgeous lambdas.
Cheers, Nick