Many projects are building on Substrate (Polkadot), but where should we look at?

Substrate is a powerful blockchain and some crypto projects building on it seem pretty innovative.

There are hundreds of projects building on Substrate, but just a few (6 to be exact) of them have study cases: Acala (DeFi), Astar (Smart Contracts), Equilibrium (DeFi), Moonbeam (Smart Contracts), Polkadex (DeFi, Infrastructure) and Unique (NFT, Gaming).

Each case study presents some challenges faced by a project and how they will be solved through the use of Substrate. There is also a "Result" section with key points for the conclusion.

It looks like just a few of them will ever become Polkadot parachains.

So, my question is simple: Is there any specific project there that is worth looking at?