I couldn't resist to make a list of the potential members that a British Confederation could feature if they would have been created in the mid 1700s and it had lasted until today.
I have counted up to 218, even more than UN members!
1.Abu Dhabi, 2.Aden, 3.Ajman, 4.Alabama, 5.Alaska, 6.Alberta, 7.Andaman and Nicobar Islands, 8.Andhra Pradesh, 9.Anguilla, 10.Antigua and Barbuda, 11.Arizona, 12.Arkansas, 13.Arunachal Pradesh, 14.Ascension and Tristan da Cunha, 15.Assam, 16.Bahamas, 17.Bahrain, 18.Barbados, 19.Belize, 20.Bermuda, 21.Bihar, 22.Bhutan, 23.Botswana, 24.Brunei, 25.Burma, 26.California, 27.Cape of Good Hope, 28.Cayman Islands, 29.Chandigar, 30.Chattisgar, 31.Christmas and Cocos Islands, 32.Chuuk, 33.Colorado, 34.(British) Columbia, 35.Connecticut, 36.Cook Islands, 37.Cyprus, 38.Dadra and Nagar Haveli, 39.Daman and Diu, 40.Delaware, 41.Dominica, 42.Dubai, 43.East Bengal*, 44.England, 45.Falkland Islands, 46.Fiji, 47.Florida, 48.Fujairah, 49.(The) Gambia, 50.Georgia, 51.Ghana, 52.Gibraltar, 53.Goa, 54.Grenada, 55.Guam, 56.Guernsey, 57.Gujarat, 58.Guyana, 59.Haryana, 60.Hawaii, 61.Himachal Pradesh, 62.Hong Kong, 63.Idaho, 64.Illinois, 65.Indiana, 66.Iowa, 67.Ireland*, 68.Isle of Man, 69.Jamaica, 70.Jarkhand, 71.Jersey, 72.Johor, 73.Kansas, 74.Karnataka, 75.Kashmir*, 76.Kedah, 77.Kelantan, 78.Kentucky, 79.Kenya, 80.Kerala, 81.Kiribati, 82.Kosrae, 83.Kuwait, 84.Laccadive Islands, 85.Lesotho, 86.Liberia, 87.Louisiana, 88.Madhya Pradesh, 89.Maharashtra, 90.Maine, 91.Malacca, 92.Malawi, 93.Maldives, 94.Malta, 95.Manipur, 96.Manitoba, 97.Marshall Islands, 98.Maryland, 99.Massachusetts, 100.Mauritius*, 101.Meghalaya, 102.Michigan, 103.Minnesota, 104.Mississippi, 105.Missouri, 106.Mizaram, 107.Montana, 108.Montserrat, 109.Nagaland, 110.Namibia, 111.Natal, 112.Nauru, 113.Nebraska, 114.Negeri Sembilan, 115.Nevada, 116.New Brunswick, 117.New Hampshire, 118.New South Wales, 119.New Jersey, 120.New Mexico, 121.New York, 122.New Zealand, 123.Newfoundland and Labrador, 124.Nigeria*, 125.Niue, 126.Norfolk Island, 127.North Australia, 128.North Carolina, 129.North Dakota, 130.Northern Cameroons*, 131.Northern Mariana Islands, 132.Nova Scotia, 133.Nunavut*, 134.Ohio, 135.Oklahoma, 136.Oman, 137.Ontario, 138.Orange River, 139.Oregon, 140.Orissa, 141.Pahang, 142.Pakistan, 143.Palau, 144.Papua New Guinea, 145.Perak, 146.Perlis, 147.Penang, 148.Pennsylvania, 149.Pitcairn Islands, 150.Pohnpei, 151.Pondicherry, 152.Prince Edward Island, 153.Puerto Rico, 154.Punjab, 155.Qatar, 156.Quebec, 157.Queensland, 158.Rajasthan, 159.Ras al-Khaima, 160.Rhode Island, 161.Sabah, 162.Saint Helena, 163.Saint Kitts and Nevis, 164.Saint Lucia, 165.Saint Vincent and the Grenadines, 166.Samoa*, 167.Sarawak, 168.Saskatchewan, 169.Scotland, 170.Selangor, 171.Seychelles, 172.Sharjah, 173.Sierra Leone, 174.Sikkim, 175.Singapore, 176.Socotra, 177.Solomon Islands, 178.Somaliland, 179.South Australia, 180.South Carolina, 181.South Dakota, 182.Southern Cameroons*, 183.Sri Lanka, 184.Swaziland, 185.Tamil Nadu, 186.Tanganyka, 187.Tasmania, 188.Telangana, 189.Tennessee, 190.Terengganu, 191.Texas, 192.Tonga, 193.Transvaal, 194.Trinidad and Tobago, 195.Tripura, 196.Turks and Caicos, 197.Tuvalu, 198.Uganda, 199.Umm al-Quwain, 200.Utah, 201.Uttar Pradesh, 202.Uttarakhand, 203.Vanuatu, 204.Vermont, 205.Victoria, 206.Virgin Islands*, 207.Virginia*, 208.Wales, 209.Washington, 210.West Bengal, 211.Western Australia, 212.Wisconsin, 213.Wyoming, 214.Yap, 215.Yukon, 216.Zambia, 217.Zanzibar and 218.Zimbabwe.
* Countries/ territories that due to the confederation would be different today:
- East Bengal (more or less Bangla Desh)
- Ireland (would be unified)
- Kashmir (would be unified)
- Mauritius (would include the Chagos islands)
- Nigeria (not divided in states)
- Northern Cameroons (separated from Nigeria, as it's not federalized)
- Nunavut (would include all the former Northern territories of Canada)
- Samoa (would be unified)
- Southern Cameroons (separated from both Nigeria and Cameroon)
- Virgin Islands (would be unified)
- Virginia (would be unified; Civil War intended to not happening in this scenario)
NOTE: the South African states are kept as in the 1910 Union, not provincialization likely in this scenario.