altcoin 

And alternative cryptocurrency to bitcoin. Bitcoin being the first cryptocurrency, any variation thereon is an Altcoin (or alt-coin)

"Litecoin is my favourite altcoin because it makes ASIC mining more difficulty"

"Namecoin is sort of an altcoin, but also a domain name system"

altcoin by Vinceypoos December 3, 2013

Altcoinative 

An new alternative to the altcoins already available in the crypto currency scene.

Platinumcoin and limxcoin are altcoinatives to litecoin and darkcoin.

Altcoinative by Cointopay January 6, 2015