Later in patch 8.15, there's a new raid, Crucible of Storms with only two boss encounters. The new raid opens 4/16/19 in Normal and Heroic difficulties. On 4/23/19 Mythic difficulty opens as well as LFR. Raid finder requires item level 350+ to queue.

Loot:

RF	375+, 380+
Normal	390+, 395+
Heroic	405+, 410+
Mythic	420+, 425+

• Crucible of Storms
• The Restless Cabal
• Uu'nat, Harbinger of the Void

See the Wowhead guide which includes Fatboss videos.