The FAQ is a great place to start, and you might also consider this reading-rec answer I gave a while back. (So automod doesn't get mad: /u/Jon_Beveryman)

I would like to add to that list and make some adjustments, though.

• Alexander Hill's The Red Army and the Second World War (2017) is a pretty all-encompassing summary and it's pretty recent.
• Roger Reese's Red Commanders: A Social History of the Soviet Army Officer Corps, 1918-1991 (2005) and The Soviet Military Experience, 1918-1991 (1999) should be in there as well if they are not. I want to say his Stalin's Reluctant Soldiers belongs as well but it's honestly been too long since I've read it to say for sure.
• John Erickson, The Soviet High Command: A Military-Political History, 1918-1941 (2001) is very long and very dense, but is really a great look at the political and doctrinal debates of the 1930s and of course the Purges. Very important for understanding how the Red Army got to where it was in 1941 (serious command deficiencies) but also 1943-45 (masterful maneuver and ability to align ends with means).
• Any of Mark Harrison's works on Soviet industry and economics in that time period. Accounting for War and Soviet Planning in Peace and War, as well as The Soviet Defense Industry from Stalin to Khruschev (coedited with John Barber).
• Lennart Samuelson, Plans for Stalin's War Machine: Tukhachevsky and Military-Economics Planning. Pairs well with Harrison.

I have a flight to catch but I might come back and add more later. The list depends on how deep in the weeds you want to get and what your interests are - do you want pure operational history, social history of the combatants, studies on war crimes, economics, so on and so on.