The reveals are 1-Step Flip Changers Soundwave and Swindle, Warrior Megatron and Thrash, Deluxe Optimus Prime and Shockwave. Shockwave is a redeco of the Cyberverse deluxe figure. Luckily, Shockwave comes with an optional part for Mandroid (an alternate arm), so he is not a necessity to complete the BAF.
I can anticipate many wondering what the difference is between Warrior and Deluxe Megatron since the deluxe is priced much higher and while the robot modes may look similar, the alt mode is where we see the complexity at play. The more obvious feet in the warrior class' alt mode show how that toy is far simpler in terms of its transformation, which lowers parts count and cost, ect. Also the deluxe figure features more points of articulation, like hip swivels, which even Mcfarlane action figures often lack.
Megatron comparison