Top 3 Outstanding Altcoins Based on the sources provided, some suggestions can be made:

Cardano (ADA): Mentioned in multiple sources as an altcoin of note, especially with the upcoming annual membership meeting. Other sources also ranked ADA in the top 10 potential altcoins in 2024.

Ethereum (ETH): Always ranked among the top altcoins in terms of market capitalization and highly appreciated for its long-term development potential thanks to its strong ecosystem and advanced technology.

Solana (SOL): Considered one of the fastest blockchains, with an actively growing ecosystem. However, it is also important to note the recent price fluctuations of SOL.