No revenue estimate for GOG — its rating/review counts don't calibrate to sales the way Steam's do. The Steam version is estimated at $18.8K — a different platform, not this one.

Etherlords

Ether is a mysterious, omnipresent substance out of which everything in the world is made. Ether knows no barriers; everything springs from it and returns to it after death, and its flow is life itself — the life of the Ether Universe. For the intelligent dwellers of this world, ether is a source of power and pure energy, sometimes referred to as magic. They are born with this ability — using invisible currents of energy flows, they create armor, weapons and servants... Ether is the thread from which they weave their world. Enter the world of Etherlords as a champion of one of the four great magical races: the powerful Chaots, the brilliant Kinets, the empathetic Vitals, or the ruthless biomechanical Synthets. Create a powerful deck of cards to summon troops who will follow your every command: exploring the world, conquering territories, battling the minions of enemy lords and ferocious creatures unleashed by the disturbances in the flow of the Ether. Build forces, create spells, and engage in diplomacy. Collect essential resources to fuel your armies, upgrade and enhance your spell sets, and create powerful spell books for conducting duels in the best traditions of trading card gameplay. Build your own deck to summon troops that will join your trading-card styled battles. A detailed diplomacy system featuring long-term alliances and trade agreements. Four magic races, each with its own distinctive realms, spells and combat style.