BlackCoin is a Proof-of-Stake (PoS) cryptocurrency created in 2014. Users are rewarded for staking their coins to secure the network. BlackCoin's staking rewards vary between 1% to 8% per year.

Peercoin is the first Proof-of-Stake (PoS) cryptocurrency. It was created in 2012 and is one of the oldest and most reliable cryptocurrency networks in the crypto sector. The protocol was developed by Sunny King and Scott Nadel, both of whom are anonymous. Sunny King also created Primecoin and VEE.
Peercoin’s PoS consensus mechanism is now widely used in the blockchain space, and allows every network participant to be both a miner or an owner. The project is focused on creating a cryptocurrency platform that will be stable, secure, energy efficient, and distributed fairly.

WhiteCoin is a cryptocurrency protocol with a Proof-of-Stake (PoS) consensus mechanism. WhiteCoin's (XWC) marketing materials place an emphasis on security and stability, but do not present details regarding their specific technical advantages or project goals.
WhiteCoin's payment network provides a high degree of anonymity and its PoS consensus model allows XWC coin holders to earn revenue by staking their holdings.