Validation methods beside POW etc Are there other concepts for the validation of the next added block to the blockchain beside POW, POS etc.?

Of cource there are, but is there a methode that is shining out of the mass?
A methode that can be a future mechanismen better than the current ones? That needs alot less electricity etc. to validate blocks?
None that is secure in a decentralized environment. Only PoW is secure.