The answer is BRICS+.
Russia is not a founding member of NATO. NATO was established in 1949 by 12 countries, including the United States, Canada, and several Western European nations, as a collective defense organization against the Soviet Union, of which Russia was a part.
Russia is a founding member of BRICS, which originally included Brazil, Russia, India, China, and South Africa. The "BRICS+" refers to the potential expansion of this group to include other emerging economies.
Russia is not a founding member of the G7. The G7 was originally the G6, formed in 1975 by France, West Germany, Italy, Japan, the United Kingdom, and the United States. Canada joined in 1976, making it the G7. Russia was invited to join in 1997, creating the G8, but its membership was suspended in 2014.
Russia is not a founding member of the OECD. The OECD was founded in 1961 by 20 countries, primarily from Europe and North America, to promote economic growth and world trade.
Russia is not a founding member of the IMF. The IMF was established in 1944 by 44 countries at the Bretton Woods Conference to promote international monetary cooperation and exchange rate stability. Russia joined the IMF later, in 1992, after the dissolution of the Soviet Union.