Asset Based crypto derivatives mimic the behavior of assets generally not available for purchase on the blockchain. For example, these assets might instead track the price of gold or stock prices. These inner workings for this style of token are conceptually similar to crypto-backed stablecoins. They are reliant on oracles to dictate what the "on-chain" price is.
Yes, there are tokens that mimic the inverse of another asset's price movement. Due to the nature of how they work, there need to be limits for the price range over which the price is valid.
For example, the iBTC token decreases in price when BTC price increases. Buying iBTC would be equivalent to short-selling BTC.