Okay, spoilers. Not everything, because the seasons are blurring together. I wish they'd cancel it.
Amara's thank-you gift to Dean was to bring back Mary Winchester. The woman FINALLY gets tp wear something other than that white nightgown she was torched in. She gets her feet back under her about when the British Men of Letters arrive. They're absolute gits, every one of them. They love torture and Sam gets the brunt. They want to eradicate the American MoL because Americans are so primitive. They brainwash Mary but she breaks free of it and much satisfactory killing occurs.
Lucifer breaks free of prison. I think Rowena did it, and then he ganks her. He inhabits a few different meatsuits and does the nasty with a GF of one of the meatsuits. She gets pregnant, which means--nephilim ahoy! EVERYBODY goes after her to either off here before the baby arrives or to protect her. Castiel wins her trust and protects her until she gives birth and dies.
Nephilim have accelerated growth rates, because about 3 minutes after the birth Jack (the kid) is an adolescent. Sam and Dean bring Jack to the Lair and the usual back-and-forth happens for several episodes. Same wants to give Jack a chance because of Sam's own history with demon blood, and Dean wants to gank the kid before he goes darkside.
EVERYBODY wants Jack. Including Asmodeus, the new king of Hell. Lucifer's imprisoned again (I think) and Jack (now about 16) does a masterful job of teenage angst. Also, don't make Jack angry. You won't like Jack when he's angry.
A rift between words has appeared. Lucifer drags Mary into it. Alt-earth is gray and sepia toned and it's not a happy place. Michael is alive there and immediately fights Lucifer, putting him and Mary into iron cages and--surprise--torturing them. Sam, Dean, and Jack use a new character's power to create a rift and jump through it. Only Jack ends up where Lucifer and Mary are; Sam and Dean end up in a jungle-type world.
Jack frees Mary. Lucifer got free, but I don't recall how. On alt-Earth the angels are still dicks. Bobby is alive there and leading the war against them. Sam and Dean get back to regular earth. Asmodeus is still trying to get Jack into his clutches and he reveals a ringer: Gabriel in a cell with his mouth sewn shut. There's also a new prophet, whose character name continually escapes me. He's fun, but of course he loses it and goes rogue.
Now the guys are gathering magical artifacts to...do something...but I can't remember what. Also, Rowena resurrected herself because magic. She manipulated Sam and he gave her a page from a spell book which she used to make herself all glowing blue and super-powerful.
After Rowena's spell and Gabriel's prison glimpse we haven't seen anything of them.
Pterofan knows everything I've missed, I'm sure.