The Evergreen Cube is 360 a Modern-legal Peasant+ environment. This means that cards are restricted to:
In addition, the Evergreen name refers to an additional restriction, namely that cards cannot contain any non-evergreen (https://mtg.gamepedia.com/Evergreen) keywords.
At a previous job, I had a number of colleagues who had recently learned how to play Magic and were starting to learn how to Booster Draft, which naturally led me to want to introduce them to cube. since my primary cube is definitely not new-player friendly, I decided to try and design something that would replicate the feeling of a typical booster draft of a modern Magic set (albeit at a significantly higher average power-level).
Since the emulation and feeling of a modern Magic set was a distinct goal for the cube, archetypes were chosen based on their ubiquity across modern magic sets. The archetypes should feel familiar and seem extremely intuitive to any player who has done at least one retail Booster Draft.
Similarly, there are subthemes in some colors to help newer players recognize and practice paying attention to the different aspects of cards. For example, white has a mildly parasitic Soldier tribal subtheme while red has a Goblin tribal theme.
Lastly, the final goal of the cube is to still allow enough strategic depth and dynamic gameplay that even players who are experienced drafters and skilled Magic players can find the games interesting and fun.
Given that the cube is pulling from common themes across all Modern-legal sets, the power level of the cube is probably best described as "Each player should feel like their deck was the best deck at a Masters power level draft, but instead of opening bombs, they opened really good fixing."
The power level across cards is relatively flat - this is to ensure that players have a high degree of agency in choosing what direction they want to take their draft and aren't immediately pulled in a specific direction by an obvious power outlier.
Core color-pair strategies are based on classic archetypes:
Azorius - "Blink". Blue and white decks will use spells that exile and return creatures to play, combined with creatures that have powerful "Enters the Battlefield" effects.
Dimir - Reanimator. Blue and black decks will use self-mill and discard effects to put powerful and expensive creatures into the graveyard, and cast spells to return them to play.
Rakdos - Sacrifice. Black and red decks will generate card and game advantage by sacrificing their own creatures.
Gruul - Creature-based Mid-Range. Red and Green decks will use cheap mana accelerating creatures to cast efficient creature spells ahead of curve, as well as Red damage spells to attack profitably or finish their opponent directly.
Selesnya - Go-wide & +1/+1 Counters. Green and white decks will create a large board of creatures via creature token creation and will play effects to make those tokens larger to eventually swarm their opponents.
Orzhov - Token Sacrifice. White and black decks will generate evasive tokens, use cards to increase their power, and sacrifice them for incremental advantage.
Boros - Aggressive Go-wide Tokens. White and red Decks will create large numbers of tokens and play one-time effects to attempt to swarm opponents before they can develop a meaningful board to defend with.
Izzet - Spells Matter. Blue and red decks will trigger abilities every time they cast Instants and Sorceries, as well as drawing cards and using red damage spells to control the board or clear the way for attackers.
Simic - Mana Ramp. Blue and Green decks will accelerate the amount of mana they have in play via mana creatures and spells. They will then play expensive, powerful creatures and spells to take over the game while also drawing additional cards.
Golgari - Graveyard Value. Black and green decks will fill their graveyards via self-mill, combat, and discard. They will then play effects that allow them to recur cards from their graveyard to eventually out-resource their opponents.