Below are 10 notable sustainable Altcoins that you may consider adding to your investment portfolio:

1. Ethereum (ETH)

The largest and most widely used smart contract platform. Ethereum 2.0 has improved performance and reduced transaction fees.

Platform for DeFi, NFT

2. Binance Coin (BNB)

The token of the Binance exchange, used in many services, including transaction fee discounts.

Supports the Binance Smart Chain ecosystem, attracting many DeFi and NFT projects.

3. Cardano (ADA)

Focuses on sustainability and scalability with the PoS (Proof of Stake) protocol.

Used in educational, healthcare, and resource management projects.

4. Solana (SOL)

A blockchain with fast transaction speeds and low fees, attracting many NFT and DeFi projects.

One of the main competitors of Ethereum.

5. Polygon (MATIC)

Reason: Layer-2 scaling solution for Ethereum, helping to reduce fees and increase transaction speeds.

Integrated by many major projects, supporting the development of Web3.

6. Chainlink (LINK)

Reason: Provides decentralized data for smart contracts, very important in the DeFi ecosystem.

Acts as a bridge between real-world data and blockchain.

7. Avalanche (AVAX)

Reason: A blockchain platform with high compatibility, low transaction fees, and fast confirmation times.

8. Cosmos (ATOM)

Reason: Focuses on interoperability between blockchains, creating the "Internet of Blockchains’

9. XRP (Ripple)

Reason: Focuses on cross-border payments with fast speeds and low costs.

10. Arbitrum (ARB)

Reason: A Layer-2 solution on Ethereum, aimed at reducing transaction fees and speeding up processing.