Bitcoin Gold (BTG) is a Bitcoin hard fork that took place in 2017. The initial goal behind creation of Bitcoin Gold was to increase level of decentralization of Bitcoin network as it became obvious that most of the network is controlled by few mining pools.
OST is currently based on cryptocurrency Ethereum protocol and serves as the currency of the OST ecosystem. The token is represented on the number of exchange platforms paired with other cryptos.
The 0x (ZRX) token is an Ethereum-based token operating as the native token of the 0x protocol. It is noteworthy that the 0x protocol represents an open-source framework for developers. The protocol facilitates both ERC-20 and ERC-721 assets. It aims to make transactions get settled in the off-chain mode to improve overall performance of decentralized exchange.