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Peercoin (formerly PPCoin) is an altcoin that was one of the first to combine the Proof-of-Stake and Proof-of-Work mechanisms.

Proof of Stake is a consensus algorithm in which the right to create blocks depends on the number of coins locked by a participant rather than on computing power.

Proof of Work is a consensus algorithm in which the right to add a block and receive a reward depends on the amount of computational work done to find a hash.

Proof of Activity is a hybrid consensus algorithm that combines the Proof of Work and Proof of Stake mechanisms to increase the security and resilience of the network.

Proof-of-Burn is a consensus algorithm in which a participant irreversibly destroys a portion of coins in order to earn the right to create blocks and claim a reward in the network.

Proof of Capacity is a consensus algorithm in which miners use free space on storage drives instead of energy-intensive computations, which makes mining coins cheaper and more environmentally friendly.

Proof of Importance is a consensus algorithm that takes into account not only the size of the balance but also a participant's activity in the network when distributing the right to create blocks.

Proof of Service is a mechanism in which nodes perform useful functions for the network and receive a reward for this, provided they hold a fixed collateral of coins.

Delegated Proof of Stake is a consensus algorithm in which coin holders vote to choose a limited number of trusted nodes that create blocks on behalf of the entire network.

Coin age is a metric calculated as the amount of cryptocurrency multiplied by the time it has been held. The concept is used in proof-of-stake mechanisms.