Gruul (red/green) is one of the most aggressive color combinations in Magic The Gathering. Gruul colors have access to plenty of different strategies and archetypes within them. Many of them play the game as fast as possible, beating their opponents before they have a chance to set up in the first place.
The strength of Gruul is how powerful their threats can be and how quickly they can get them onto the battlefield. If unchecked, it's not uncommon to get a quick win. However, Gruul can struggle with card draw and run out of steam if not careful. Losing a hand with ramp and big creatures might not be a big deal since you can swing in for so much damage.
7 Auras
While Auras weren't always a big Gruul archetype, with the release of the Upgrades Unleashed Commander preconstructed deck and the addition of modified from Kamigawa: Neon Dynasty, they've gotten rather good at it. Aura decks want to be slamming down as many Auras as possible onto your creatures, often for value.
Thanks to the green side of Gruul, there is a lot of enchantress support, meaning cards that let you draw or trigger effects whenever you cast an enchantment. The red side of the Auras can buff creatures to make them into more significant threats. Cards like Ancestral Mask, Rancor, and Sticky Fingers are all good choices for an Aura Gruul deck.
6 Primal Surge
Primal Surge is a unique archetype within Gruul, based around the card Primal Surge. Primal Surge lets you exile the top card of your library and put it onto the battlefield if it's a permanent, repeating the process as many times as you want. As such, it's not uncommon for a Primal Surge deck to only contain permanents and no instants or sorcery spells.
Gruul has access to many hard-to-cast but powerful cards, making Primal Surge capable of winning the game the turn it is cast. Since you only want permanents in your deck, ramp often comes from creatures, usually mana dorks. Primal Surge does cost ten mana to cast, making it take a while to get to it. However, once resolved, you can potentially put your entire deck onto the battlefield.
5 Treasures
Gruul is one of the best color combinations at making Treasures, making it a powerful archetype within the color combination. Many cards from the Dungeon & Dragons and Streets Of New Capenna sets have provided Treasure support for Gruul decks, giving you Treasures for simply doing what you already want to be doing.
Gruul Treasure decks have no problems accessing mana, letting them play a higher mana curve to play large, impactful spells. Goldspan Dragon, Tireless Provisioner, and Xorn all help you make extra Treasure tokens, letting you cast your big mana Gruul spells. Gruul also has a lot of support related to artifacts, something that all Treasure tokens are.
4 Exile
The Exile archetype wants to exile cards, only to cast them afterward. Often, there are permanents with effects that trigger when doing so, such as Faldorn, Dread Wolf Herald, and Laelia, the Blade Reforged. Red is especially good at this, with cards like Light Up The Stage and Jeska's Will letting you easily set up your exile for casting for little mana.
The green side of the Exile archetype generally helps with ramp or protection. Cascade is also a key part of the archetype, as the spell you cast from a cascade trigger is cast from exile. Adventure cards are good to include, as after casting the adventure side, they are exiled until you want to cast the creature side of them.
3 Stompy
Stompy is one of the most well-known Gruul archetypes. Stompy decks are incredibly aggressive, putting down low-mana creatures to win the game as soon as possible. It's common for Gruul Stompy decks not to include any card with a mana value of more than four, usually Questing Beast being the highest end.
Embercleave is the most popular game-ender, as giving a creature double strike and trample is incredibly powerful. While Stompy isn't common in Commander due to having three (or more) other opponents, it's a staple in formats like Standard and Pioneer. Gruul has access to powerful creatures that can be cast for cheap, such as Lovestruck Beast and Ulvenwald Oddity.
2 +1/+1 Counters
Gruul can easily spread +1/+1 counters, making it a fantastic archetype within the colors. It's easy to stack counters on a creature with cards like the partners Halana and Alena, who can put +1/+1 counters on a creature for free. Since counters count as being modified, Kamigawa: Neon Dynasty has greatly boosted the strategy.
Plenty of cards that give creatures haste in Gruul, making creatures with counters even more dangerous. +1/+1 counters have a burn sub-theme, letting you deal damage based on counters on creatures with something like Thundering Raiju.
1 Landfall
One of Gruul's strongest archetypes is landfall. Green is the color of ramp, making it far and away the best color for putting multiple lands onto the battlefield in a turn. Adding red into the mix gives you access to even more aggressive threats that let you push your board state to its limits. Moraug, Fury of Akoum can lead to you winning the game, as each landfall trigger will give you an extra combat phase to deal massive damage.
Many cards in green can interact with lands in the graveyard, putting them back onto the battlefield. Utilizing that, you can get two landfall triggers off of fetchlands. Landfall decks are explosive, potentially leading to a giant battlefield of creatures in just one turn. Since green is part of Gruul, you can even play protection spells such as Heroic Intervention to ensure your battlefield stays safe since you are likely to be a target for a board wipe.