Some of the most commonly used cryptocurrencies for online gambling are:
Bitcoin (BTC)
It was the first of all cryptocurrencies, Bitcoin was created in 2009 by an anonymous person, or perhaps a group of people, called Satoshi Nakamoto. It is still the most widely used cryptocurrency and will be available as an option for any online casino that accepts cryptocurrencies. It is one of the most secure cryptocurrencies, while Bitcoin casinos are the most widespread type of crypto casinos out there.
Ethereum (ETH)
Ethereum was one of the first altcoins available. It is popularly used in ICOs and IPOs, and is now part of the mainstream in the cryptocurrency world. It is considered the second most popular cryptocurrency after Bitcoin and is used by cryptocurrency users who want to save money on transaction fees. An Ethereum casino may accept only ETH or also work with other cryptocurrencies.
Bitcoin Cash (BCH)
Many probably associate it with Bitcoin itself, but Bitcoin Cash is a completely different cryptocurrency. It is the result of a hard fork* of Bitcoin in 2018 and, because it is quite close to BTC, it has gained popularity. It is also an option among people who want to save on transaction fees and we can say that it is one of the most used cryptocurrencies on gambling sites around the world.
Litecoin (LTC)
Litecoin emerged in 2013 and is quite similar to BTC. However, what sets Litecoin apart is how fast transactions are made with this currency. This feature is highly appreciated by those playing at Litecoin casinos.
Ripple (XRP)
Ripple is primarily known as a global gross settlement system rather than a payment option. It is the destination for crypto users, who are mainly concerned about processing fees. It is a cheap option for cryptocurrency trading, and is therefore popular among online players.
Cardano (ADA)
ADA has been around since 2015 and is also widely used in online casino.
*A hard fork is a radical change to a bitcoin protocol that makes previously invalid blocks and transactions valid, or vice-versa.