Well, the first target would probably be having more surviving Commonwealth Realms. Most of the big ones- India, Pakistan, Kenya and so forth, are probably not possible, but with the right PoD you could probably get South Africa, possibly some sort of Zimbabwe-Rhodesia like state, Mauritius, Trinidad and Tobago, Guyana, Dominica, Malta, Fiji, Kiribati, Samoa, Nauru, etc. etc.
Though if we're taking 1900 as the start point, Irish Home Rule in 1914, followed by a Dominion of India in the 20s and the Empire gradually evolving in that direction might see more on this front.