Is there a decentralized version of USDT ? or any project is doing it? I feel the centralized version has huge risk to invest. If there is no project, I would love to gather a bunch of people to develop it.
Yes. There is Nubits and BitUSD.
Nubits is decentralized and runs its own ledger whilst BitUSD relies on the Bitshares blockchain. I have no idea how nubits work since it's just so complicated but it has indeed held its value over the past few years so that's a good sign. BitUSD is generated from people shorting a particular currency.
There is also steem dollars, similar to BitUSD, but very volatile.
USDT is supposedly decentralized, but its value obviously still relies on the reserves of tether. The coins aforementioned do not.