Poor little Unison always gets neglected. Yet it was pretty much BUILT for widening. Comb filters, if used properly can add a chorus effect. And yeah, the Chorus is pretty much a widener too.
M Class Stereo can also widen.
You have a lot of options with the stock devices, as well as several RE devices that will work (and have been mentioned). Still, I love the Unison device, if used judiciously and properly.
And please for the love of good music, do not start widening everything in your mix. Balance is your friend.