Though no press announcement was ever released, it appears that Iceland signed the Artemis Accords sometime in October, according to small mention in the the press release announcing the signing of the Netherlands.
The mention was so small I missed it. In fact, so apparently did NASA, as Iceland did not issue its own press release. The U.S. likely found out about the signing through private diplomatic communications.
This brings the total number of nations now part of this American space alliance to thirty-one, as follows: Argentina, Australia, Bahrain, Brazil, Canada, Columbia, Czech Republic, Ecuador, France, Germany, India, Iceland, Israel, Italy, Japan, Luxembourg, Mexico, the Netherlands, New Zealand, Nigeria, Poland, Romania, Rwanda, Saudi Arabia, Singapore, South Korea, Spain, the United Kingdom, the United Arab Emirates, the Ukraine, and the United States.