TrueUSD is a stablecoin backed by USD. It was created by TrustToken, a company that specializes in creating asset-backed tokens on the Ethereum blockchain. TrueUSD is fully collateralized and is transparently verified by third-party attestations.
TrueUSD was created within a legal framework that enables users to exchange USD directly with an escrow account. The platform is powered by smart contracts that ensure a 1:1 parity between USD and TrueUSD. Escrow accounts and regulatory compliance practices enable auditing and more legal protection for token holders.
Users wire funds to these third-party escrow accounts, and an equivalent amount of TUSD is generated to their ethereum addresses. Each TUSD can be redeemed for one US Dollar, that is held in escrow.

Steem Dollars, or Steem Based Dollars, are stablecoins released by the Steem platform and pegged to the USD. Steem Dollars (SBD) are one of the three currencies that help power the Steem social media platform. SBD holders are entitled to receive one dollars worth of STEEM when it is redeemed.

Gold Bits Coin is developing a digital currency that is backed by gold. They hope to create a digital asset with less price volatility that can be used as a medium of exchange. GBC is built on Ethereum. Their marketing materials are unclear about how much gold they have in reserve to back each Etherreum-based token.