TCP/UDP/IP are BE, but that's largely an artifact of the time they were invented (when the LE/BE split was more even), hence networking hardware is probably where BE is still commonplace.

Most application protocols I've worked with are LE; serialisations like Avro, BSON, capnproto, protobufs, etc. come to mind, as well as numerous other proprietary ones. ASN.1 is a notable exception, but it's also much older.