As of my last update, several DeFi protocols and platforms have gained significant popularity within the decentralized finance ecosystem. Here are some of the most notable ones:

Uniswap

Uniswap is a decentralized exchange (DEX) that operates on the Ethereum blockchain. It enables users to swap various ERC-20 tokens directly with one another without the need for intermediaries. Uniswap uses an automated market maker (AMM) model and liquidity pools to facilitate trading.

Compound

Compound is a decentralized lending protocol that allows users to lend and borrow cryptocurrencies. Users can earn interest by supplying assets to lending pools or borrow assets by collateralizing their holdings. Interest rates are algorithmically determined based on supply and demand.

Aave

Aave is another decentralized lending protocol on Ethereum that enables users to lend, borrow, and earn interest on cryptocurrencies. Aave offers unique features such as flash loans, which allow users to borrow assets without collateral for a single transaction.

MakerDAO

MakerDAO is a decentralized autonomous organization (DAO) that governs the Maker Protocol, which issues the stablecoin Dai (DAI). Users can generate Dai by locking up collateral assets (e.g., Ethereum) in smart contracts called Vaults. MakerDAO also operates the Dai Savings Rate (DSR), which allows users to earn interest on Dai holdings.

Synthetix

Synthetix is a decentralized synthetic asset issuance protocol on Ethereum. It enables the creation and trading of synthetic assets (synths) that track the value of real-world assets such as fiat currencies, commodities, and cryptocurrencies. Users can mint synths by staking collateral in the form of SNX tokens.

Yearn.Finance

Yearn.Finance is a decentralized yield aggregator that optimizes DeFi yield farming strategies on behalf of users. It automatically reallocates funds across various lending protocols and liquidity pools to maximize returns. Yearn.Finance also operates the yEarn (YFI) token, which is used for governance and fee-sharing.

Curve Finance

Curve Finance is a decentralized exchange optimized for stablecoin trading and low-slippage swaps. It provides liquidity pools with low fees and minimal slippage for stablecoin trading pairs, making it popular among traders and liquidity providers.

Balancer

Balancer is a decentralized automated portfolio manager and liquidity provider on Ethereum. It allows users to create custom liquidity pools with multiple assets and different weights, enabling flexible asset allocation and automated trading strategies.

SushiSwap

SushiSwap is a decentralized exchange forked from Uniswap with additional features such as yield farming, staking, and decentralized governance. It operates on Ethereum and aims to provide enhanced liquidity and incentives for users.

These are just a few examples of popular DeFi protocols and platforms within the decentralized finance ecosystem. The DeFi landscape is continually evolving, with new protocols, platforms, and innovations emerging to address the growing demand for decentralized financial services.