Trading and battling game Axie Infinity took the Earn-to-Play by storm and even broke out into the mainstream. The game uses a two-token economy: Smooth Love Potion (SLP) for in-game actions and Axie Infinity Shards (AXS) to receive tangible rewards for playing. With AXS, players have a revenue stream, as well as can vote on proposals by the Axie community.
Axie Infinity was developed and released by Sky Mavis, who have also built a custom sidechain Ronin to support this and their other games. Ronin uses Proof-of-Stake, where the stake is denominated in AXS. Staked AXS gets allocated to the Community Treasury, and the rewards to stakers are also sourced from it. And of course, AXS is the primary currency of the Axie NFT marketplace, where users trade SLP and Axies.