This falls to the topic of consensus mechanisms that are the requirement to confirm transactions that happens on the blockchain. Other way include the proof stake. Unlike the proof of work that provides reward to the first very first miner who can solve the problem, here, miners didn't receive block rewards, but they receive transaction fees.
In addition, proof of stake is more energy efficient because it doesn't need complex sums to be solved, unlike the proof of work, wherein cryptographic sums that miners are tasked to solve is harder.
This is hard to find another alternative but for me there is another consensus algorithm that can be find in Ethereum and others, that is Proof of Stake or PoS. This is used to find the node valid according to its investments.