Michael Oliver and Anthony Taylor (England), Danny Makkelie (Netherlands) and Daniel Siebert (Germany) have not been allocated to officiate at a game as yet. Neither has the two women FIFA appointed refs. The cynics amongst us may feel it may have something to do with the “One Love” campaign and FIFA’s acquiescing to Qatar’s policies on women. Daniel Orsato (Italy) has been given two games to referee.
Oliver's got Japan v Costa Rica, Makkelie's got the plum Spain v Germany game and Siebert did Australia v Tunisia. You're right about the three female refs though as none have yet been assigned a game.
Oliver and Makkelie announced today and Siebert yesterday, following media criticism. There are 36 referees at the World Cup and 12 games in Orsato has had two.