[xerxespoy]

Take your pick: https://coingecko.com

While many of these are forks of Bitcoin and use similarly wasteful proof mechanisms, many are also completely new and different. Several different consensus mechanisms are broadly used across these, most of which improve drastically on Bitcoins wasteful Proof of Work (PoW). Some even solve the problem with only very negligible energy footprint, such as the variations on Byzantine Fault Tolerance (BFT). It's been long-debated whether those alternatives trade safety for energy-savings, but after many years it would appear the reverse is true. The majority of projects that have succumbed to some kind of system-inherent weakness have been PoW protocols being "51% attacked", which is generally not a concern for the alternatives.