[attr="value"]       /*  =   exact */
[class~="box"]       /*  ~=  has word */
[class|="icon"]      /*  |=  exact, or prefix (eg, value-) */
[href$=".doc"]       /*  $=  ends in */
[class*="-is-"]      /*  *=  contains */

h3 + p               /*  +   adjacent sibling */
article ~ footer     /*  ~   far sibling */
.container > .box    /*  >   direct child */

:target (h2#foo:target)
:disabled

:nth-child
:nth-child(3n)
:nth-child(3n+2)
:nth-child(-n+4)
:nth-last-child(...)

:first-of-type
:last-of-type
:nth-of-type
:only-of-type   - only child of its parent thats like that

:only-child