Summer Variation is a subset for when your last layer edges are oriented in which you use your last slot to orient the last layer corners. This set is a little bit less known by cubers because it's not super important after you learn WV, but it is quite useful if all of your last layer edges are already oriented upon creation/insertion of your last pair. With LCEO, Summer Variation becomes an even more versatile solving tool since you can do it in any solve without worrying about the edges since you fix them right after.
Alg Count - 27
Alg Count - 27