Altcoins are alternative coins to Bitcoin. When considering investing in an altcoin, it is important to consider factors such as market capitalization, adoption and use cases, and team and development. The top undervalued altcoins with 100x potential include Polkadot (DOT), Solana (SOL), Cosmos (ATOM), Celer Network (CELR), Chainlink (LINK), Ocean Protocol (OCEAN), Enjin (ENJ), Origin Protocol (OGN), Harmony (ONE), and Elrond (EGLD).