Mig-21 Fishbed. Introduced half a century ago. Over 10,000 were built. Capable of Mach 2 speeds. Used extensively in Vietnam
and in the 60s and 70s wars in the Middle East. Still in use in a number of Third World countries.
Mig-23 FLOGGER - designed to be a successor to Mig-21, a fighter-interceptor, also had ground attack capabilities.
Entered service in the early 1970s. Still in service in a number of Third World countries.
Mi-24 Hind helicopter gunship. Introduced in the mid 1970s, saw extensive combat in a number of wars - from Cambodian - Vietnamese war of 1978, through Soviet invasion of Afghanistan,
through both Gulf Wars. Still in service, primarily in Russia and former Warsaw Pact countries, and a number of Middle Eastern and African countries.
According to Wikipedia, United States operates some for training purposes (as an opposing force).