Main core of the deck is of course:

Sarkhan's Unsealing 

Was building a GR Unsealing deck (Ghalta etc) but then found this beauty when looking for more cheap creatures to trigger Core Card Sarkhans Unsealing. So i changed to B for Yargle, and Amnit, B also has better Options for Boardwipes to reset, and some Card Draw options. 

Source of deck BR Idea:

Strictly Better MTG
https://www.youtube.com/watch?v=67B_cOR4eQ4

The decklist on this site was a little bit tweaked by me cause of preferences, and MTG Arena setting, so mythics dont cost bucks, just WC or Availabilty. 

The Maybeboard

It includes mostly Other Options for Triggering Sarkhans Unsealing. Since a bunch can just be fillers with 4, 5 Power.
Important jank cards are Inferno Hellion and Yargle. (They trigger bigger Boom).

Just below i point out some special Cards that trigger and add good Effects to the deck:

• Demanding Dragon, Noxious Gearhulk (and Storm fleet Arsonist) add some Sacrifice/Destroy. 
  
  
• Combustible Gearhulk, dmg or draw.
  
  
• Demon of Dark schemes, Light Boardwipe and Trigger 
  
  
• Razaketh, the Foulblooded: Allows to Tutor for Sarkhans Unsealing (demon or the scheme). Demonic Tutor, Razakeths Rite and Final Parting are also Options to Tutor for Unsealing. 
  
  
• Heart Pierce Manticore: sac Yargle/helion = Value. 
  
  
• Neheb, the Eternal, also works nice, but doing dmg in second Main doesnt add more Mana. 
  
  
•  The  Big 'Uns: Yargle, Inferno Hellion, ... Also Possible in BR are Silverclad Ferocidons, Razaketh, Torgaar, 
  
  
• I also like adding some boardwipes to the deck like sweltering suns (bonus cycling). 
  Or maybe Yahennis Expertise, alot of 3 Drops that have 4 Attack. 
  
  
• Maybe add some Evolving Wilds, and Thaumatic Compass, for better fixing, although Deck curves out at mostly 4 and 5 mana. It needs alot of double R or double B. 

Others Worthy Mentions:

• For me noteworthy are Dire Fleet Ravager and Combat Celebrant but mythics. They do add even more opportunity to burn Opp HP down.
  
  
• Or Hazoret and Rekindling Phoenix if you already have RDW, they are hard to remove creatures and trigger aswell.
• For fun: Wanted Scoundrel, prob. cheapest trigger i could find.

• For draw: Prob stick to Glint-Sleeve, maybe Add Live Fast, draws and adds Energy

Strictly better MTG Original values Budget, both his and mine want Fun. 

Sidethought: Wish it wouldnt crash so often when writing descritpion RIP.