Crypto startup Ether Cards sold $3.7 million worth of souped-up non-fungible tokens (NFTs) in a pre-sale that closed earlier this month.

The graduate of ConsenSys’ accelerator program told CoinDesk collectors snapped up 1,752 total cards, including pieces by veteran comic book artist Mark McKenna and Dirty Robot, a Japan-based visual designer. A wider public sale of the remaining 8,250 cards, some of them rare, opens Thursday.

The sale serves as an early validation for Ether Cards’ gamified twist on collectible NFTs. Each card carries a smart-contract-based “trait” designed to prompt continued user engagement. For example, some might grant their holders discounts on future pack purchases, while others might increase the likelihood of a future “rare” pull.

That’s a stark difference from many of the NFTs that have swamped the digital art world in recent weeks, said Andras Kristof, Ether Cards co-founder. He said second-order “utility” traits bolster Ether Cards’ value proposition, granting them staying power that, say, a tokenized photo of someone’s cat utterly lacks.

“What you can do right now with NFTs is you can buy, you can sell and you can hold. And I think we can do better than that,” Kristof said.

The randomization of each NFT’s traits is generated by Chainlink’s “Verifiable Randomness Function.”

“As NFTs become more popular, we anticipate that more and more projects will rely on Chainlink VRF as a means to prove the uniqueness and rarity of their NFT,” Chainlink co-founder Sergey Nazarov told CoinDesk. “Relying on unverifiable sources of NFT generation often leads to fraudulent manipulation, calling into question the very value of an NFT series.”

Just last week, digital artist Beeple watched in disbelief as his tokenized composite of 5,000 prints sold at auction for a record $69 million. It was a historic moment for NFTs as a medium – but also seen by some as troubling because massive sales could lead to an over-exuberant market for what are really just digitally traced JPEGs.

“After this project gains traction, nobody can afford to create a plain old NFT and get away with it,” Kristof said.

Ether Cards will release its framework for minting supercharged NFTs in the public domain – likely under MIT’s highly permissive software license, Kristof said. Doing so would let anyone iterate on Ether Cards’ NFT framework so long as they make their version similarly open.

Kristof said the framework would allow other creators to monetize blockchain-stored pieces.

Ether Cards did not tell CoinDesk by press time whether participating artists would take home a share of the profits.