diacritical marks for symbols

Left harpoon above ; Enclosing circle backslash

Right harpoon above ;  Left right arrow above

Long vertical line overlay   

Anticlockwise arrow above ; White up-pointing triangle

clockwise arrow above
asterisk above

left arrow above 
right arrow above

ring overlay

clockwise ring overlay 
anticlockwise ring overlay 
enclosing upward pointing triangle 

three dots above ;

Four dots above ; rightwards harpoon with barb downwards 
  fourth derivative

enclosing circle
  JIS composition circle

enclosing square
white square
ten thousands sign

white circle
large circle
ideographic number zero 

enclosing circle backslash prohibition

enclosing screen
clear screen symbol 
enclosing keycap

reverse solidus overlay
reverse solidus

double vertical stroke overlay
anotation finite function diacritic
double vertical line

annuity symboL
= actuarial bend
right ceiling

triple underdOT 
wide bridge above
= contraction operator
extends the full width of the base character 
bridge above 
leftwards arrow overlay 
leftwards arrow

long double solidus overlay
long double slash overlay

leftwards harpoon with barb downwards 
left arrow below 
Enclosing diamond; Right arrow below 
  white diamond 
short vertical line overlay
occasional variant for negation