This was from a quick survey of my Twitter feed. Is this a complete list? Obviously not. This is just a snapshot in time of what I'm currently aware of. It'll be an interesting read in a year when everything changes.
Oh, it's pretty important to have a nice landing page with a good description and/or whitepaper. I made a long list of projects, but had to edit out a bunch because some projects just didn't have enough of a landing page.
Project Serum is a protocol for DeFi for Solana. What makes it different is it's "on-chain orderbook" design. The reasoning behind this design is that decentralized exchanges like Uniswap requires Automated Market Making (AMM). In AMM, there's no limit orders, bids or offers, etc. The only price is the current market price. This is a necessary limitation because Uniswap is built on the Ethereum network, and providing matching bids and offers will involve lots of operations and quickly become cost prohibitive.
There are a lot of projects
Figment Learn is probably the fastest onramp to learning development for Solana. It's probably also the fastest onramp to learning the other projects they have pathways for, like Polkadot and Polygon.
Phantom is a browser extension wallet where you can keep your SOL. It's the most recommended wallet for beginners in this ecosystems since it offers a friendly UI. This wallet is also compatible with SPL tokens.
Another reason to use the framework is it provides a "standard" API for building smart contracts on Solana and could be the de-facto solution for a majority of programs written for Solana.
Pyth provides real-time on-chain market data, which would be instrumental in any derivatives product built on the blockchain. It lists a lot of heavy hitters as data providers, like FTX, Jane Street, and IEX (of Flash Boys fame).
It's 2021 and NFTs are all the rage. Solanart is the first NFT marketplace on Solana. I'm pretty ignorant about this whole NFT craze at the moment, but even I recognize the importance of idea of non-fungible tokens so I'll definitely have to spend some time learning more about the NFT market in general.
Check out some interesting projects, like Degen Ape Academy and Sollamas.
Raydium is an AMM platform for Solana built to provide on-chain liquidity to Project Serum's central limit order book.
Saber is a cross-chain stablecoin exchange on Solana. This means it helps to facilitate the transfer of assets between Solana and other blockchains.
SolFarm aggregates yield farms from Raydium and Saber. I don't know much about yield farming at this point, but this definitely merits further investigation.
PsyOptions is a protocol for building American-style options. Like most of crypto, the project isn't very mature (as of writing), but having a mature protocol for writing options contracts for cryptocurrencies will lead towards more mainstream adoption by players in the financial markets.
I saw Zeta present about their experience in the Solana Ignition Hackathon. Their tagline is "the premier under-collateralized DeFi options platform". I have no idea what that means, but the project seems interesting, mostly because of my interest in trading options.
Flux Protocol is a cross-chain oracle aggregator that will be launching on Solana. As with all crypto projects, who knows when this will happen. Hopefully this will make writing smart contracts dependent on an oracle much easier.
Hedgehog is a prediction market platform built on Solana (testnet for now). They're currently in open beta so it would be interesting to know what kinds of prediction markets eventually make it.
Most Solana projects try to tackle the financial markets aspect of blockchain, but Grapes Network tries to tackle social networking.
Wormhole is a protocol for communication between different blockchains. Version 2 is currently in "active development". The main use of the protocol would be as a bridge between ERC-20 and SPL tokens.
Mango Markets is a pretty hot decentralized exchange, or so it seems on Twitter.
Many of the projects are at various stages of development, but that seems to be the case with Solana and blockchain in general. What makes Solana so exciting the the multitudes of project currently being developed. A lot of these project also came out of the Solana Ignition or have big backers like FTX.