The following link points to a csv file containing data on real GDP per capita for a little over 100 countries from 1960 to the present:Penn World Table and included only countries that had data available for each year starting in 1960. The Python code used to construct the datasets and the figure is available from this Github repository.
The following links are to data files that can be used to assess the quantity theory of money. The first contains only long-run average rates of money growth, inflation, and real GDP growth. The second contains the same variables plus average currency depreciation and lending rates.
The data files were constructed using data from the World Bank's World Development Indicators. The money supply measure is M2, the price level is the consumer price index, and national income is real GDP in constant year US dollars. For each country with at least 10 overlapping continuous years of data for each series, the average annual growth rates in money, prices, and real GDP were computed. The data sets have different numbers of observations because exchange rate and interest data is available for fewer countries.
The World Bank classifies countries by income level. As of July 2021, the World Bank classified countries based on GNI per capita in 2020 according to the following thresholds:
Programs for generating the data sets are available in this Github repository.