doubleofive said:
I understand it as:
Old Republic
Clone Wars/Prequels
The Dark Times (forbidden by GL)
The OT
New Republic Era (dates are given by ABY, after the Battle of Yavin)
Legacy Era (I think this is a comic series)
I think that's pretty much it. There are Legacy books and then there are Legacy Comics, which aren't related. I think the "Legacy Era" refers to the comics.