There was SCTP and a couple others but in practice anything not TCP or UDP is blocked by middle boxes and also NAT traversal is a problem. QUIC has been success

There was SCTP and a couple others but in practice anything not TCP or UDP is blocked by middle boxes and also NAT traversal is a problem. QUIC has been successful but that rides on top of UDP. Specialized networks (eg telecom backhauls) still see use of specialized protocols and those are large deployments. The big thing that's been an ongoing experiment in networking with mixed results is IPv6 which is at a lower level of the stack.