Boros: This is almost good enough, but I think its ultimately worse than Lightning Helix and Nahiri
The variety of life-gain enchantments are also useful not removing the combat step entirely, just softening the blow or making us the least appealing target
and Cardfight

Amulet of Unmaking Anguished Unmaking Aragorn, King of Gondor Azusa, Lost but Seeking Azusa, Lost but Seeking Baron, Airship Kingdom Barrin's Unmaking Basking Broodscale Basking Capybara Basking Rootwalla Besieged Viking Village Black Bolt, Inhuman King Black Panther, Wakandan King Blinking Spirit Brago, King Eternal Breaking // Entering Breaking // Entering Breaking Point Breaking Wave Breaking of the Fellowship Brimaz, King of Oreskos Bumi, King of Three Trials Chicken la King Choking Fumes Choking Miasma Choking Restraints Choking Sands Choking Tethers Choking Vines Claim the Kingdom Contraband Kingpin Cooking Campsite Croaking Counterpart Darien, King of Kjeldor Dauthi Voidwalker Doctor Doom, King of Latveria Earth King's Lieutenant Earth Kingdom General Earth Kingdom Jailer Earth Kingdom Protectors Earth Kingdom Soldier Earthshaking Si Edgar, King of Figaro Esquire of the King Evendo, Waking Haven Feasting Troll King Flanking Licid (playtest) Flanking Troops Frolicking Familiar Frolicking Familiar Furygale Flocking Giott, King of the Dwarves Goblin King Grunn, the Lonely King Harald, King of Skemfar Hulking Bugbear Hulking Cyclops Hulking Devil Hulking Goblin Hulking Metamorph Hulking Ogre Hulking Raptor Huntmaster Liger Idol of the Deep King Illuna, Apex of Wishes Ithilien Kingfisher Kadena, Slinking Sorcerer Karumonix, the Rat King Katara, Seeking Revenge Kenrith, the Returned King Kenrith, the Returned King King Cheetah

In decks that are playing a lot of Auras and/or Equipment, Halvar gives them a massive boost to give them double strike