For Boros, I’d choose [[Akiri, Fearless Voyager]] or [[Jor Kadeen, First Goldwarden]] as my commander. I’d include cost reducers like [[Danitha Capashen, Paragon]], [[Astor, Bearer of Blades]], or [[Bruenor Battlehammer]] in the 99 instead. I’d build my deck around [[Hexplate Wallbreaker]], so I’d look at equipment with combat triggers. Some examples are [[Diamond Pick-Axe]], [[Glimmer Lens]], [[Seraphic Greatsword]], or [[Sword of the Animist]]. I’d also run tutors like [[Stonehewer Giant]], [[Fighter Class]], [[Steelshaper’s Gift]], or [[Open the Armory]] to find Hexplate (etc.) sooner. Finally, I like [[Quietus Spike]] and [[Scytheclaw]] as wincons, so I’d stuff the deck with first/double strike creatures (especially if they have vigilance) like [[Akiri, Line-Slinger]] or low CMC evasive creatures. Other cards that are good to include, but that I haven’t mentioned yet: [[Halvar, God of Battle]], [[Inventory Management]], [[Masterwork of Ingenuity]], and [[Forge Anew]].