Liechtenstein will first have to become a member of UNESCO before it can sign the World Heritage Convention. A dispute with the Czech Republic concerning Lednice-Valtice seems to be at the origin of the non-accession.

https://francais.radio.cz/confiscations-restitutions-la-famille-liechtenstein-propose-un-reglement-a-8798187

Good news indeed concerning Nauru, the smallest republic in the world, its only potential inscription being in my opinion the lunar landscape and the various rusty industrial infrastructures linked to the exploitation of phosphates.

Las Medulas came to mind, but I'm not sure Nauru's landscape has quite the same visual appeal.

1) Not in Unesco (9):
Liechtenstein, Kosovo (1 WHS), Northern Cyprus (Cyprus), Taiwan (China), Western Sahara (one T-site) (Morocco), Transnistria (Moldova), Abkhazia (Georgia), South Ossetia (Georgia), Somaliland (Somalia))

2) Unesco members which didn't sign the WH convention (0):

3) Member states and special territories with no T-list (10):
Timor Leste, Equatorial Guinea, Niue, Brunei, French Guyana (France), Faroe (Denmark), Falkland and Southern Georgia (UK), Chagos (UK), Tokelau (NZ), Nauru.

4) Member states and special territories with T-list but no sites proposed (17):
Tonga, Bahamas, Swaziland, Burundi, Samoa, Bhutan, Trinidad Tobago, Grenada, Liberia, Djibouti, British Caribbean (UK), Jan Mayen and Svalbard (Norway), Marianas and Guam (USA), Tuvalu, Somalia, Sao Tome, Kuwait.

5) Member states and special territories with sites proposed but none inscribed not currently pursuing nomination (1):
Guyana.

6) Member states and special territories with sites proposed but none inscribed currently pursuing nomination (8):
Monaco (2019), Guinea Bissau (2025), Comoros (2026), Maldives, Cook Islands, St Vincent, Sierra Leone (2025), South Sudan.

7) Member states and special territories with only one site inscribed and no tentative list (4):
Belize, Puerto Rico (USA), New Caledonia (France), French Caribbean (France) (Singapore, Kiribati, Luxemburg).

8) Member states and special territories with only one site inscribed with a tentative list not pursuing further nominations (17):
Barbados, St. Kitts and Nevis, Vanuatu, Solomons, El Salvador, Haiti, PNG, St. Helena (UK), Fiji, Qatar, Guinea, Lesotho, Dominica, Antigua Barbuda, Angola, Eritrea, Dutch Caribbean..

9) Member states and special territories with only one site inscribed with further sites proposed not currently pursuing further nominations (6):
Gabon (Ref 2005), Paraguay (Rej 2005), Marshalls (Incompl 2010), Palau (Incompl 2010), Zambia (Def 2014), Moldova (withd 2017).

10) Member states and special territories with only one site inscribed currently pursuing further nominations (8):
UAE (2025), Jamaica (2025), Dominican Rep. (2021), Mozambique (2025), Andorra, Togo, Micronesia, Cabo Verde (2026).

Rwanda, French Polynesia, Congo Rep. are out.

Gabon had its second WHS inscribed in 2021 in is now out of the list as well. Djibouti, Eritrea and Dom. Rep. are also on our Bubbling Under list.

So in general there has been some progress since 2021:

Three African countries are out of the list with two sites each (Gabon, Rwanda and Rep. of Congo) as well as French Polynesia, which has similarly got two WHS.
The French Caribbean islands have received their first WHS (in Martinique).
With Tuvalu and Nauru joining the WHS treaty, all UNESCO members can now submit WHS.
The first tentative lists have been submitted for Tuvalu, Cook Islands, Somalia and Sao Tome and Principe.
2025 will see Sierra Leone and Guinea Bissau proposing their first WHS as well as Mozambique and UAE their second one. 2026 will have the Comoros proposing their first WHS and Jamaica and Cabo Verde their second one.
Other missing countries bubbling under are Djibouti, Cook Islands, South Sudan and St Vincent and Grenadines for their first WHS as well as Micronesia, Dominican Republic, Andorra, Eritrea and Togo for their second one.
Kuwait, the Maldives and Monaco, which all seemed active to some extent during the last couple of years attempting their first inscriptions, all seem inactive at the moment. The same applies to member states which have submitted in the past, but now seem inactive (Guyana, Zambia, Palau, Marshalls, Moldova, Paraguay).

1) Not in Unesco (9):
Liechtenstein, Kosovo (1 WHS), Northern Cyprus (Cyprus), Taiwan (China), Western Sahara (one T-site) (Morocco), Transnistria (Moldova), Abkhazia (Georgia), South Ossetia (Georgia), Somaliland (Somalia))

2) Unesco members which didn't sign the WH convention (0):

3) Member states and special territories with no T-list (10):
Timor Leste (working on first T-list), Equatorial Guinea (working on first T-list), Niue, Brunei, French Guyana (France), Faroe (Denmark), Falkland and Southern Georgia (UK), Chagos (UK), Tokelau (NZ), Nauru.

4) Member states and special territories with T-list but no sites proposed (15):
Tonga, Bahamas, Swaziland, Burundi, Samoa, Bhutan, Trinidad Tobago, Grenada, British Caribbean (UK), Jan Mayen and Svalbard (Norway), Marianas and Guam (USA), Tuvalu, Somalia, Kuwait, Maldives.

5) Member states and special territories with sites proposed but none inscribed not currently pursuing nomination (2):
Guyana (2001), Monaco (2019).

6) Member states and special territories with sites proposed but none inscribed currently pursuing nomination (9):
Guinea Bissau (2025), Comoros (2026), Cook Islands (2027), St Vincent, Djibouti, Sierra Leone (2025), South Sudan, Sao Tome and Principe (2026), Liberia (2028).

7) Member states and special territories with only one site inscribed and no tentative list (6):
Belize (working on new T-list), Puerto Rico (USA), New Caledonia (France), French Caribbean (France), Luxemburg, Kiribati (working on new T-list).

8) Member states and special territories with only one site inscribed with a tentative list not currently pursuing further nominations (17):
Barbados, St. Kitts and Nevis, Vanuatu, Solomons, El Salvador, Haiti, PNG, St. Helena (UK), Fiji, Qatar, Guinea (working on new T-list), Lesotho, Dominica, Antigua Barbuda, Angola, Dutch Caribbean.

9) Member states and special territories with only one site inscribed with further sites proposed not currently pursuing further nominations (4):
Paraguay (Rej 2005), Marshalls (Incompl 2010), Palau (Incompl 2010), Moldova (withd 2017).

10) Member states and special territories with only one site inscribed currently pursuing further nominations (11):
UAE (2025), Jamaica (2025), Dominican Rep. , Mozambique (2025), Andorra (2027), Togo, Micronesia, Cabo Verde (2027), Singapore (2027), Eritrea, Zambia.

It's done.

News concerning 3 countries: Saint Vincent and the Grenadines, Grenada and the Bahamas.
https://www.unesco.org/en/articles/saint-vincent-and-grenadines-hosts-capacity-building-session-world-heritage-convention

1) Not in Unesco (9):
Liechtenstein, Kosovo (1 WHS), Northern Cyprus (Cyprus), Taiwan (China), Western Sahara (one T-site) (Morocco), Transnistria (Moldova), Abkhazia (Georgia), South Ossetia (Georgia), Somaliland (Somalia))

2) Unesco members which didn't sign the WH convention (0):

3) Member states and special territories with no T-list (9 - 4 UNESCO members):
Timor Leste (working on first T-list), Niue, Nauru, Brunei, French Guyana (France), Faroe (Denmark), Falkland and Southern Georgia (UK), Chagos (UK), Tokelau (NZ).

4) Member states and special territories with T-list but no sites proposed (16):
Tonga, Bahamas, Swaziland, Burundi, Samoa, Bhutan, Trinidad Tobago, Grenada, British Caribbean (UK), Jan Mayen and Svalbard (Norway), Marianas and Guam (USA), Tuvalu, Somalia, Kuwait, Maldives, Equatorial Guinea.

5) Member states and special territories with sites proposed but none inscribed not currently pursuing nomination (2):
Guyana (2001), Monaco (2019).

6) Member states and special territories with sites proposed but none inscribed currently pursuing nomination (7):
Comoros (2026), Cook Islands (2027), St Vincent, Djibouti, South Sudan, Sao Tome and Principe (2026), Liberia (2028).

7) Member states and special territories with only one site inscribed and no tentative list (8):
Belize (working on new T-list), Puerto Rico (USA), New Caledonia (France), French Caribbean (France), Luxemburg, Kiribati (working on new T-list), Guinea-Bissao, Sierra Leone.

8) Member states and special territories with only one site inscribed with a tentative list not currently pursuing further nominations (16):
Barbados, St. Kitts and Nevis, Vanuatu, Solomons, El Salvador, Haiti, PNG, St. Helena (UK), Fiji, Qatar, Guinea, Lesotho, Dominica, Antigua Barbuda, Angola, Dutch Caribbean.

9) Member states and special territories with only one site inscribed with further sites proposed not currently pursuing further nominations (4):
Paraguay (Rej 2005), Marshalls (Incompl 2010), Palau (Incompl 2010), Moldova (withd 2017).

10) Member states and special territories with only one site inscribed currently pursuing further nominations (8):
Dominican Rep., Andorra (2027), Togo, Micronesia, Cabo Verde (2027), Singapore (2027), Eritrea, Zambia.

UAE, Jamaica and Mozambique have received their second WHS and are out.