Brick Red Coat and Hat Trimmed with Velvet Roses

Brick red coat with quilted collar, cuffs and patch pockets, with a satin-covered toque-style hat with a small brim, trimmed with red velvet roses.
The Queen chose this look for the graduation of her grandson, Prince William, as a commissioned officer in the British Army during the Sovereign's Parade at the Royal Military Academy Sandhurst on 15 December 2006. She complemented the red fabric with the ruby and diamond Australian Hibiscus brooch:

The Queen wore this outfit again on 16 April 2010 to attend the Newbury horse races. No brooch was used:

On 30 November 2011, the Queen selected this look again for a visit to the Musuem of Liverpool (during which HM met Yoko Ono), accessorizing with her Grima ruby and Yellow gold brooch:

Unfortunately, I have no reliable info on the whereabouts of this coatless appearance, complete with Red Flower Posy brooch:

Pearl Grey Dress and Striped Jacket Combo

This chic neutral ensamble in pearl grey, with a collarless jacket in contrasting stripes of opaque and shiny fabric and silver-tone buttons was worn on 20 May 2003, accessorized with the Frosted Sunflower brooch, to the Chelsea Flower Show:

The Queen repeated the outfit, this time pairing it with the Pearl Trefoil brooch, on 15 April 2009, for audiences at Windsor Castle, during which she received, among others, the Governor of South Australia Kevin Scarce:

 

Primrose Yellow Coat and Dress with Green Piping

This ensamble, made for the Golden Jubilee wardrobe, is comprised of a primrose yellow coat and dress with pale green piping, in a lightweight crepe fabric. The coat is collarless features flap pockets and gold and pearl buttons. A pale green straw hat with yellow ribbon detailing was also made, although this is/was rarely seen.

The Queen wore this outfit for a visit to the Chelsea Flower Show on 20 May 2002, pairing it with the Australian Wattle brooch:

 

Probably the most high profile appearance in this outfit was made on 27 June 2002, when the Queen visited Portsmouth during her Golden Jubilee tour of the UK. The Cullinan V brooch was selected for the occasion:

 

This outfit was repeated on 11 June 2004 for Trooping the Colour. The Household Cavalry badge, the usual choice for such an occasion, was worn:

 

 

 

 

The dress was worn alone on 26 May 2010, for audiences at Buckingham Palace, when the Queen received, among others, the Ambassador of China, His Excellency Mr Liu Xiaoming. The brooch used looks like it might be the Pearl Triangle:

 

 

Black Coat with White Shawl Collar

This black coat with white silk satin piping and a pleated shawl collar in the same fabric has been paired either with a black straw hat with white silk satin covered crown and oversized black silk ribbon or with a more sombre all-black fabric covered hat.
Below we see the outfit worn to a wreath lying ceremony at Devlin Castle in Bratsilava, Slovakia, on the first of a two-day tour of Slovakia on 23 October 2008, paired with the impressive pearl and diamond Richmond brooch and the first of the two hats:

 

On 25 April 2015, the Queen selected this coat again, this time paired with a black fabric-covered hat we've seen many times before and the Queen Mother's Palm Leaf brooch, to attend a service at the Cenotaph in London to commemorate the 100th anniversary of the Gallipoli campaign. She was accompanied by the Duke of Edinburgh and the Duke of Cambridge:

 



 

 

Later on, the original hat made a reappearance when the Queen changed into it for a service of commemoration and thanksgiving at Westminster Abbey to mark ANZAC Day (link to the Daily Mail article with full story):

 

 

Lilac Stewart Parvin Outfit and Feathered Philip Somerville Hat

This outfit is comprised of a lavender silk floral print dress and lilac crepe coat, both by Stewart Parvin, and a matching Philip Somerville hat in lilac straw trimmed with a single sage green feather.

This outfit made its first appearance way back on 20 November 2007, when the Queen and the Duke of Edinburgh paid a private visit to Malta to coincide with their 60th wedding anniversary (below, the Queen with Prime Minister Dr Lawrence Gonzi). Not many photos are available of the event, although it can be clearly seen that Her Majesty is wearing the Kent Amethyst brooch:

 

On 15 June 2008, the dress that goes with this coat made its first solo appearance when the Queen chose it for a tour of Windsor Castle with US President George W. Bush and First Lady Laura Bush. The six-petal flower brooch was used:

 

 

Later in the day, the full outfit was on show when the Queen presented awards at the Vivari Queen's Cup Final at the Guards Polo Club in Windsor:

 

 

On 9 June 2010, the Queen wore again the dress on its own when she presented Lord Naren Patel of Dunkeld with the insignia of Knight of the Thistle during an audience at Buckingham Palace. Isn't this dress gorgeous, with its dainty side bow? One of Queen Victoria's Bow brooches was worn:

Then, on 12 July 2010, the complete outfit made its debut at the Ceremony of the Keys at the Palace of Holyroodhouse in Edinburgh, Scotland, when the Queen accessorized her coat with the Kent Amethyst brooch:

 

 

Later the same day, the Queen was photographed again in this outfit when she visited the Queen Mother Memorial Garden at the Royal Botanic Garden Edinburgh:

 

 

 

A year later, on 22 June 2011, the Queen repeated this look for a visit to Alnwick Gardens in Northumberland, this time selecting her amethyst bouquet brooch:

 

 

On 19 July 2011, we got a first peek at the dress made for this outfit, when the Queen wore it for audiences at Buckingham Palace with, among others, the Ambassador of Togo, Calixte Batossie Madjoulba (it remains hidden in the photo below, but the Kent Amethyst brooch was repeated):

 

 

The outfit was worn again for the Easter Sunday service at St George's Chapel, Windsor Castle, on 8 April 2012, accessorized with the Duchess of Cambridge's Pearl Pendant brooch:

 

 

On 21 July 2014, we got a proper look at the dress that goes with this coat. Isn't it gorgeous, with its dainty side bow? The Queen wore her six-petal flower diamond brooch for private audiences at Buckingham Palace with Sir Simon Rattle (directly below) and Dame Quentin Bryce, the outgoing Governor General of Australia (below):

 

 

On 14 June 2015, the Queen repeated the outfit to attend the Cartier Queen's Cup Final at the Guards' Polo Club in Windsor (Daily Mail article here). She wore the Nizam of Hyderabad Rose brooch: