Here's a list of the top 25 most intelligent nations based on various metrics such as literacy rates, education levels, scientific research output, and other indicators.

1. Finland: Consistently ranked high in PISA (Programme for International Student Assessment) scores, Finland excels in literacy, math, and science.

2. South Korea: Known for its rigorous education system, South Korea consistently ranks high in PISA scores and has a high literacy rate.

3. Canada: Canada has a strong education system, high literacy rates, and a high level of scientific research output

4. Netherlands: The Netherlands has a highly educated population, with a strong focus on science, technology, engineering, arts, and mathematics (STEAM) fields

5. Switzerland: Switzerland is renowned for its excellent education system, high literacy rates, and strong scientific research output.

6. Denmark: Denmark has a high level of education attainment, low poverty rates, and a strong focus on innovation and entrepreneurship.

7. Singapore: Singapore is known for its highly competitive education system, with a strong focus on STEAM fields and a high literacy rate.

8. New Zealand: New Zealand has a well-regarded education system, high literacy rates, and a strong focus on environmental sustainability.

9. Australia: Australia has a highly educated population, with a strong focus on STEAM fields and a high level of scientific research output.