I'm thinking of all the units formed from soldiers of former and then-current colonies, Caribbean, Indian, African, Australian, etc.
Were they all busy elsewhere? How were they used on D-Day if they were in Normandy?
As a Canadian we hear often about Juno Beach, a little less about the British and Americans, and nothing about our other allies' contributions.
After the spring of 1942. the Australians pulled the three divisions they had in North Africa back to defend Australia. After May 1942, they fought in New Guinea and nearby South Pacific islands. There was one rather good New Zealand division that stayed in North Africa and participated in the Italian campaign. South Africa also contributed one division that fought in North Africa and the Italian campaign. General Slim's 14th Army in Burma had two divisions of troops, the West African rifles, who primarily came from Nigeria and the East African rifles, that came from Kenya and Uganda.
Source: "Order of Battle: Western Allied Forces of World War II" by Michael Haskew
It is also worth noting the large numbers of British (30 percent) landed on Juno with the Canadians. As well English speaking Canadians (politicians, military and the general public) wanted a big role, the British who were still not over the Somme were happy to let them take it.
Source: CP Stacey
Arms, Men and Governments: The War Policies of Canada, 1939-1945
Official History of the Canadian Army in the Second World War Vol 3