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.

BitBay is developing a decentralized marketplace based on a non-colateralized stablecoin. Unlike other stabelcoins, BitBay is stabilized with a dynamic peg that is meant to reduce volatility without anchoring the price to another asset. The network has a Proof-of-Stake (PoS) consensus mechanism.

Dignity is a stablecoin pegged to gold, that was developed by the company Cryptobontix. Each DIG token is pegged to the worth of 0.02445 grams of gold, which was worth exactly $1.00 at the time of the Dignity whitepaper.
Cryptobontix's portfolio of stablecoins are based on a partnership with bullion suppliers. Each individual token acts as a security on a 15-year convertible mortgage. The DIG token is pegged to the value of gold. Every year, 1/15th of the tokens can be redeemed for gold valued at around $1.00.
Cryptobontix does not actually own all of the physical gold. The company plans on spending its profits on acquiring the actual bullion that token holders will have the option of converting.