I believe the title says it all. There are many proof of stake cryptocurrencies out there (Cardano etc). Also there are many blockchains that are not ...
source https://www.google.com/url?rct=j&sa=t&url=https://stackoverflow.com/questions/52732221/proof-of-stake-consensus-in-non-cryptocurrency-blockchains&ct=ga&cd=CAIyGmM2Nzk3ODA2ZWViNjVjODI6Y29tOmVuOlVT&usg=AFQjCNEFsD4EtvINahP1_3Xi3Pu3_gXpQQ
