https://mtgdecks.net/guides/modern-boros-energy-deck-tech-sideboard-guide-mtg-357

https://www.tcgplayer.com/content/article/Modern-Boros-Energy-MTG-Deck-Guide/ef05257c-889b-47dc-80e1-0ccb65ff6f04/

Boros and Mardu Energy
In: 1 Showdown of the Skalds, 1 Ghost Vacuum, 1 Celestial Purge, 1 Dismember, and 1 Wrath of the Skies
Out: 3 Ragavan, Nimble Pilferer, and 2 Static Prison

Eldrazi Ramp
In: 2 Obsidian Charmaw, 2 Wear // Tear, 1 Ghost Vacuum, 2 Blood Moon, and 1 Molten Rain
Out: 4 Galvanic Discharge, 2 Thraben Charm, and 2 Ranger-Captain of Eos

Dimir Oculus
In: 1 Celestial Purge, 1 Ghost Vacuum, 1 Showdown of the Skalds, and 1 Dismember
Out: 4 Ocelot Pride

Amulet Titan
In: 1 Orim's Chant, 2 Wear // Tear, 2 Blood Moon, 2 Obsidian Charmaw, and 1 Molten Rain
Out: 2 Phlage, Titan of Fire's Fury, 2 Fable of the Mirror-Breaker, and 4 Galvanic Discharge

Golgari Yawgmoth
In: 1 Showdown of the Skalds, 1 Ghost Vacuum, 1 Celestial Purge, 1 Dismember, 1 Stone of Erech, and 1 Wrath of the Skies
Out: 3 Ragavan, Nimble Pilferer, 2 Ranger-Captain of Eos, and 1 Ocelot Pride

Charbelcher Combo
In: 1 Orim's Chant, 2 Wear // Tear, 1 Stony Silence, and 1 Molten Rain
Out: 1 Goblin Bombardment, 2 Thraben Charm, 1 Fable of the Mirror-Breaker, and 1 Phlage, Titan of Fire's Fury

Broodscale Combo
In: 2 Wear // Tear, 1 Stony Silence, 1 Wrath of the Skies, 1 Dismember, and 1 Showdown of the Skalds
Out: 3 Ragavan, Nimble Pilferer, 2 Ranger-Captain of Eos, and 1 Ocelot Pride

Ruby Storm
In: 1 Orim's Chant, 1 Ghost Vacuum, and 1 Stone of Erech
Out: 1 Fable of the Mirror-Breaker, 1 Phlage, Titan of Fire's Fury, and 1 Seasoned Pyromancer

Orzhov Blink
In: 1 Showdown of the Skalds, 2 Wear // Tear, 1 Celestial Purge, and 1 Dismember
Out: 3 Static Prison and 2 Ragavan, Nimble Pilferer

Domain Rhinos
In: 1 Wrath of the Skies, 1 Orim's Chant, and 2 Blood Moon
Out: 3 Galvanic Discharge and 1 Goblin Bombardment

https://www.channelfireball.com/article/Modern-Boros-Energy-MTG-Deck-Guide/3e44c955-6f9a-4435-84dd-94168ff65733/

Vs BOROS ENERGY
The mirror is very much play-draw-dependent. On the play, I love Ragavan, Nimble Pilferer in the matchup even though it can get brick-walled by Ocelot Pride or Ajani, Nacatl Pariah. A turn-one Ragavan backed up with removal has the potential to break the game with card and mana advantage.

Being on the draw, however, is different as I do not want to draw any Ragavans throughout the game. The five cards I bring in will be two cards that counteract each other in some way — Chained to the Rocks and Wrath of the Skies — not something particularly proud of, but you do need an extra one drop removal spell when being on the draw, and having access to Wrath of the Skies can be back-breaking if you can shape your game around it.

On the Play

Out: -1 Blood Moon and -1 Ragavan, Nimble Pilferer
In: +1 Showdown of the Skalds and +1 Ghost Vacuum
On the Draw:

Out: -1 Blood Moon and -4 Ragavan, Nimble Pilferer
In: +1 Showdown of the Skalds, +1 Ghost Vacuum, +1 Wrath of the Skies, and +2 Chained to the Rocks

Vs TEMUR BREACH
I'm going to be honest, this is a bad match-up game one. But, you can turn the game around post-sideboard quite a lot. You have all the tools to win with the right amount of pressure combined with the many hateful pieces you bring in games two (and three).

The biggest reason to play the four Ragavan, Nimble Pilferer is for this match-up, the card gives you speed to be able to develop your hate pieces while holding up mana for Orim's Chant or Wear // Tear. Keep in mind that Stony Silence will shut off your Treasure tokens, but if the Temur Breach player wants to combo, they'll have to remove of the Stony Silence first. Then, you'll be able to use them again during their combo turn.

I cut all copies of Ocelot Pride because they're bad against Pyroclasm and Tamiyo, Seasoned Scholar's plus one ability, also quite slow clock and I prefer all the other threats.

Out: -4 Ocelot Pride, -2 Phlage, Titan of Fire's Fury, -1 Fable of the Mirror Breaker, and -1 Goblin Bombardment
In: +1 Wrath of the Skies, +3 Stony Silence, +2 Orim's Chant, and +2 Wear // Tear

Vs ELDRAZI RAMP
Eldrazi Ramp is a tough match-up, probably the worst for Boros Energy. You'll have to watch out for Kozilek's Return, where Goblin Bombardment is the best card you have to answer it. Obsidian Charmaw is good, of course, but not as broken as you think as Eldrazi Ramp plays a fair few Forests, and they'll know how to sequence them first in the post-sideboard games. Despite this, Obsidian Charmaw and Arena of Glory is a true beating. Ghost Vacuum is secretly a great card here since it can exile Kozilek's Return from the graveyard as well as makes Emrakul, the Promised End's mana cost a bit more expensive.

Out: -4 Galvanic Discharge and -2 Thraben Charm
In: +3 Obsidian Charmaw, +2 Wear // Tear, and +1 Ghost Vacuum

Vs DIMIR OCCULUS
Dimir Oculus is a good match-up as long as they don't reanimate a fast Abhorrent Oculus in the early turns. Ocelot Pride is the worst card in the deck since they'll be good at removing your Guide of Souls, as well as playing sweepers and Orcish Bowmaster to punish Ocelot Pride. I prefer Ragavan, Nimble Pilferer much more since if unchecked can create better value than what Ocelot can achieve after a few turns.

Out: -4 Ocelot Pride
In: +2 Chained to the Rocks, +1 Ghost Vacuum, and +1 Showdown of the Skalds

Vs MARDU ENERGY
On the Play:

Out: -2 Ragavan, Nimble Pilferer
In: +1 Showdown of the Skalds and +1 Ghost Vacuum
On the Draw:

Out: -1 Blood Moon -4 and Ragavan, Nimble Pilferer
In: +1 Showdown of the Skalds, +1 Ghost Vacuum, +1 Wrath of the Skies, and +2 Chained to the Rocks

Vs AMULET TITAN
Out: -2 Phlage, Titan of Fire's Fury and -2 Fable of the Mirror-Breaker
In: +2 Orim's Chant and +2 Wear // Tear

Vs GOLGARI YAWGMOTH
Out: -4 Ragavan, Nimble Pilferer
In: +1 Showdown of the Skalds, +1 Ghost Vacuum, and +2 Chained to the Rocks

Vs CHARBELCHER COMBO
Out: -1 Blood Moon, -1 Goblin Bombardment, -2 Thraben Charm, and -2 Fable of the Mirror-Breaker
In: -1 Phlage, Titan of Fire's Fury, +2 Orim's Chant, +2 Wear // Tear, and +3 Stony Silence

Vs BROODSCALE COMBO
Out: -1 Fable of the Mirror-Breaker, -1 Goblin Bombardment, and -4 Ragavan, Nimble Pilferer
In: +2 Wear // Tear, +3 Stony Silence, and +1 Wrath of the Skies

Vs RUBY STORM
Out: -1 Blood Moon, -1 Fable of the Mirror-Breaker, and -1 Phlage, Titan of Fire's Fury
In: +2 Orim's Chant and +1 Ghost Vacuum

Vs ORZHOV EPHEMERATE
Out: -1 Blood Moon and -2 Static Prison
In: +1 Showdown of the Skalds and +2 Wear/Tear

Vs DOMAIN RHINOS
Out: -3 Galvanic Discharge, -1 Lightning Bolt, and -1 Goblin Bombardment
In: +1 Wrath of the Skies, +2 Orim's Chant, and +2 Chained to the Rocks