Erigon

staking-deposit-cli generates validator keys and deposit data for Ethereum staking, and is now maintained as the EthStaker fork that the original owners point to. Validators run it once when setting up new keys.

Reth is a modular Ethereum execution client written in Rust by Paradigm. Rust builders run it as a node or extend its components to build custom infrastructure.

Prysm is an Ethereum consensus client written in Go by Prysmatic Labs and historically the most used client. Validator and node operators run it to take part in consensus.

Lighthouse is an Ethereum consensus client written in Rust by Sigma Prime and one of the most used clients on the network. Validator and node operators run it to follow and attest to the beacon chain.

Besu is a Java Ethereum execution client hosted by LF Decentralized Trust, formerly under Hyperledger, with wide enterprise use. Node operators run it when a deployment is standardized on the Java stack.

Nethermind is an Ethereum execution client written in C# and .NET, and the second most used client on the network. Node operators and infrastructure builders run it to serve JSON-RPC and follow the chain.