4. Rob Howley
The 49-year-old is serving a ban for placing bets on more than 1,000 rugby matches over four years in breach of the game’s regulations. However, he could come into contention when his suspension ends in June 2020.
As well as acting as Gatland’s assistant with Wales, Howley took over the head coach role when the New Zealander was in charge of the British and Irish Lions in 2013 and 2017 – guiding Wales to the Six Nations title in 2013.
As a player he won 59 Wales caps and played in two Lions Tests.