Where's the UNRWA for the Millions of Refugees from Syria, Iraq, Libya, Yemen (and, Coming Soon, Afghanistan?)

Silly you, there isn't one. Those current refugees have to make do with a general, generic UN refugee body. Unlike the Palestinians, whose refugee status dates from 1948, and who, having been "displaced" by Jews and not jihadis/other Muslims, merit their very own personal UN refugee outfit (which ensures that they retain their status--and associated UN goodies--in perpetuity).