Altcoin or Alternative coins are those which are alternative to Bitcoin. There are hundreds of Altcoin, each with different individual features and functions. Bitcoin involves many problems and it is not perfect. Altcoin creates a different version of Bitcoin. The popularity of Altcoin is measured by the market capitalization, which means how much money or capital is invested in an asset when measured in dollars.
The main reason for Altcoin to emerge was to improve Bitcoin flaws and to somewhat, try to compete with bitcoin by innovating and developing new features to improve and improve on bitcoin limitations.
Another important factor was the transaction time. Many Altcoin like Litecoin (LTC) and Fast coin (FST) have blockchain update times of one minute or under, which is a lot faster than bitcoin.
Some of the examples of popular Altcoin are:-