BTC-Labnet
A fully dockerized parallel Bitcoin mainnet for research
Testnet and regtest are the usual answer when you need a Bitcoin network you can break safely, but many wallets, and hardware wallets in particular, offer limited or no support for them. That makes them a poor environment for studying how real wallets behave.
BTC-Labnet takes a different route. It is built directly from the original Bitcoin Core source code and shares the genesis block with the real network, but it runs in complete isolation from public mainnet. Wallets connect to it believing they are on mainnet, which means their behaviour can be observed exactly as it would be in production, with zero-cost transactions and full control over the chain.
It was built to support research on wallet fingerprinting and address clustering, where being able to drive real devices through real mainnet-looking transactions was the whole point.