This is a very good topic and the hardest one in my opinion.
I really like the idea to have some backed for HBD as UST is trying to do it. However, the choice of the crypto asset that shall be used it is not an easy decision.
Since we are a decentralized project we shall not use centralized cryptos like PAXG, USDT, UDSC, etc.
Currently, I only see two possible cryptos to be used, BTC and DAI.