Blue and White Naturalistic Floral Print Silk Dress

As far as I'm able to tell, we haven't seen yet a coat/jacket or a hat that match this dress. It's a simple silk dress printed with naturalistic blooms in shades of blue on a cream background which the Queen has worn for semi-formal daytime engagements.

It's first appearance that I'm aware of was on 10 May 2016, when the Queen received at Buckingham Palace delegations from both Houses of Parliament who presented loyal addresses on the occasion of HM's 90th birthday (Daily Mail article here). The dress was worn with Queen Victoria's sapphire and diamond brooch, a wedding present from Prince Albert:

A month later, on 10 June 2016, the Queen changed into this dress to host a luncheon for her Governors-General at Buckingham Palace following the National Service of Thanksgiving for her 90th birthday (she had previously worn a primrose yellow outfit for the service at St Paul's Cathedral - Daily Mail article on both events here). She also swapped brooches, opting for one of Queen Victoria's bow brooches: