It is well known that the Soviet Red Army suffered colossal losses in the first months of the war in massive encirclements such as the one in Kiev, with hundreds of thousands of soviet troops being taken prisoner. The Soviet Union famously managed to raise hundreds of fresh divisions to help stem the German advance. What is little discussed however, are the Soviet formations that maintained a fighting retreat all across the western Soviet Union. Presumably these existed, as otherwise the Soviets would have had country-sized gaps in their front lines. Does anyone know anything on the subject?
You'll be very hard pressed to find units that survived as an intact whole, unless they weren't commited to the fighting - Ultimately, the Soviet army that existed on June 22nd had ceased to exist by the end of the year. The Soviets lost 4 million men, and 229 divisional equivalents in the first year of the war (Glantz- When Titans clashed, 2015 edition) from an initial in-theatre strength of 2.7 million men. It's a tribute to the speed and efficiency of Soviet mobilization that they were able to raise units to replace such massive losses.
However, a few did make it - You can trace the units that survived by lookign at Soviet Army/Divisional formation histories and seeing which ones were reformed throughout the war. The divisions that do seem to have survived the first year of the war often ended up re-designated as Guards Divisions - e.g. 2nd Guards was formed from 127th Rifle Division, and 3rd Guards from the 153rd Rifle Division, and would likely be from the forces from Northwestern Front which didn't suffer as much from the devastating encirclements as did the forces of the Western, Southwestern and Southern Fronts.