Beam has some overlap, but in my understanding it has a rather involved syntax for defining the data flows, quite far from the simple list of connections between in and out ports that you see in FBP systems following J P Morrisons principles more closely.

Apache NiFi comes quite a lot closer, with the main difference that they only have a single in-port, instead of separate named ones. Also it seems to be among the more heavy and complex implementations (for good and bad).