There are at the moment approximately five useful smart contract types

In practical use

• payment: Send money from one address to another

• multisignature escrow: Send money to an address from which typically just 2 of 3 signatories can send it on (n of m). This contract type allows for adjucating payments.

• ICO: Raise capital for a startup by issuing a fixed number of coins

Being tested

• atomic swap: Two parties exchange an amount in one cryptocurrency for another amount in another cryptocurrency without third party.

• lightning primitives: Deposit, withdraw, transfer money from a "lightning bank" to another user at another "lightning bank", across a SWIFT-like network, while making it impossible that this "lightning bank" could steal your money.

About a sixth useful smart-contract type

A sixth useful smart-contract type does not even exist on paper, let alone in practice.

Every single, new smart contract type represents a massive breakthrough. The discovery of such thing is a world-changing event.

About the corporate "blockchain" crowd

What the corporate "blockchain" crowd is looking for, is this elusive sixth useful smart-contract type, clearly without even understanding what exactly they are looking for.