Hindenburg Research is great. They also did the Nikola expose (that bunch of shysters who claimed to have electric truck technology where their truck couldn't even move under its own power so they filmed it rolling down a gentle slope).

For anyone wanting to get into the weeds about detecting accounting fraud, the book "Financial Shenanigans" has lots of historical examples of ways company executives have cooked the books to make their public company financial statements appear more appealing to investors than they actually are.