The Magic: the Gathering Red-Green Echo deck is a creature-based strategy that uses the “Echo” mechanic to generate value and maintain a steady stream of threats. The idea is to play creatures with the “Echo” ability, which usually have a low mana cost and decent power and toughness, and then pay the additional cost to keep them on the battlefield for an extra turn.

For example, Mogg War Marshal is a common creature used in the Red-Green Echo deck. It costs only two mana to cast, and when it enters the battlefield, it creates a 1/1 Goblin token. You can then pay an additional two mana during your next upkeep to keep Mogg War Marshal on the battlefield for another turn, which will create another Goblin token. This gives you two creatures for four mana, which is a good deal. Other good examples are Pouncing Jaguar, Albino Troll, and Goblin War Buggy.

To support the creature-based strategy, the Red-Green Echo deck also includes pump spells and other support cards that can make your creatures even more powerful. Cards like Rancor, and Giant Growth can all give your creatures a temporary boost in power and toughness, making them more threatening and difficult to deal with.

Finally, the deck includes mana acceleration cards like Llanowar Elves and Birds of Paradise to help you cast your creatures faster and more consistently.

Here below is an example decklist.

Creatures
4 Albino Troll
4 Pouncing Jaguar
4 Goblin Patrol
2 Goblin War Buggy
4 Llanowar Elves
3 Simian Grunts
3 Keldon Champion

Spells
4 Rancor
4 Giant Growth
4 Lightning Bolt
2 Might of Oaks
2 Shock

Lands
4 Karplusan Forest
8 Forest
8 Mountain

Overall, the Red-Green Echo deck is a fun and powerful strategy that can generate a lot of value from your creatures and overwhelm opponents with a steady stream of threats. It requires careful deckbuilding and play to execute effectively, but can be a rewarding choice for players who enjoy creature-based strategies.