Bitcoin is both a cryptocurrency and an electronic payment system.

Nxt is an open source cryptocurrency and payment network.

Revolut is a app to exchange, send and receive 28 currencies with analytics.

Dwolla an online payment system and mobile payments network.

PayPal is an online money transfer and payments platform.

Litecoin (LTC) is a peer-to-peer cryptocurrency and open source software project.

Peercoin (PPCoin or PPC) is a peer-to-peer cryptocurrency utilizing both proof-of-stake and proof-of-work systems.

Groestlcoin is a multipurpose cryptocurrency that has instant & private transactions with minimal fees.