I'd like to know if there's a chain that smart contract is being in mainnet use of it.
Thank you for your question. This is Sota, founder of Astar Network. Astar is a multichain smart contract hub on Polakdot supporting WASM and EVM. Polkadot doesn't support smart contracts by design and this is the reason why the ecosystem needs smart contract Parachains like Astar and Moonbeam.
When it comes to smart contracts on Polkadot, there are 2 types of contracts, smart contracts on EVM and smart contracts on WASM. EVM on mainnets are already ready today and Moonbeam and Astar are supporting EVM. WASM is also going to be supported by Astar in the early Q3. Currently, we are testing WASM on our testnet and measuring the network stability and performance. Hope we can support WASM as soon as possible on Astar so that the Polkadot ecosystem can explore the new smart contract landscape.
If you are interested in WASM Smart Contracts which are executed by
pallet-contracts, these are primarily Smart Contracts which are written in the Rust based edsl ink! and which are compiled to WASM.
You might want to take a look at the awesome-ink Repo, which collects info on all avaible projects building with ink!.
So there is a testnet support available on currently 5 different Parachain testnets and hopefully the first deployment on a mainnet soon.