It depends on your definition of "interesting". Lightning Network, atomic swaps, sidechains (like Blockstream Elements, Liquid), confidential transactions, bull

It depends on your definition of "interesting". Lightning Network, atomic swaps, sidechains (like Blockstream Elements, Liquid), confidential transactions, bulletproofs, MimbleWimble, Non-Interactive Proofs of Proof-of-Work etc. are all interesting tech innovations and have nothing to do with get-rich-quick.