Focuses specifically on Japanese engines and automatic transmissions, which is a great niche if your part is from a Japanese make.

Open3-Y Nizhnelikhoborskiy Proyezd, 1А 56.007755, 37.331722

Known for selling contract engines and performing high-level repairs; they may be interested in rebuildable units. Avtobreyker Used auto parts store OpenSormovskiy Proyezd, 5 стр 3

Specializes in the "buyout" of auto parts and allows you to send a list of inventory for a quote. Khodos Avto Engine rebuilding service

A retail and wholesale store that handles a wide range of used car parts. OpenSadovaya-Kudrinskaya Ulitsa, 32

Beyond local storefronts, you should consider these three types of buyers: Sell Auto Engines and Transmissions: Expert Q&A Guide