I have heard some people talk about how big they think Defi to real world borrowing could be in the next 1-2 years, taking a loan against your BTC to buy a house or something like that appeals to many bitcoiners so Zero is great for that. Erik Vorhees has mentioned in several podacsts he bought a house borowing against ETH, Robert Breedlove was very impressed by it and Peter McCormack wants to buy a house and doesnt want to sell his BTC 
Also uncollateralised loans are another area that could potentially see exponential growth at least according to Ari Paul (Uponly podcast last 15min), this topic was once briefly discussed after a community call however there are some obvious challenges with uncollateralised loans in Defi.
I came across Mars protocol launching on Terra, they will offer uncollateralised loans to whitelisted smart contracts to limit risk.
" * Borrowers (uncollateralised): Smart contracts that borrow assets from Mars liquidity pools without posting collateral. Each smart contract credit line must be approved by governance and will include a credit limit to mitigate the protocol’s risk exposure"
Below is the link to the whitepaper, perhaps we can keep this for future reference.
Since I am not an expert in lending protocol design so maybe people from the community can give there feedback and we can get a discussion going as I think this might be a good topic to explore in the near future.