Sa'angreal are similar to, but more powerful than, angreal. The amount of the Power that can be wielded with a sa'angreal compares to the amount that can be handled with an angreal as the Power wielded with the aid of an angreal does to the amount that can be handled unaided.
Unlike angreal and sa'angreal, each ter'angreal was made to do a particular thing. Some require channeling, while others may be used by anyone. Some draw both saidin and saidar, even if only one person uses it. (ACoS,Ch20) Ter'angreal in close proximity can sometimes interact with unexpected and dangerous consequences. (TDR,Ch23)
Possible Spoilers#It had been thought that the knowledge of creating these items had been lost, but Elayne has discovered how to do so.
One does not have to actually touch an angreal to draw the One Power through it. (TFoH,Ch21)
Known angreal, sa'angreal and ter'angreal are listed in Items.