I know about District Wars existence, but not much more. Little research shows its made by Destan Entertainment, now Teyon. And I know by heart its Polish company. They have made some really bad games. They also made a game which English version I can't seem to find after years of looking - Blind Shot: Assassin's Confession. I wouldn't be surprised if they share the engine as well.
Wolfschanze 1 I remember quite a bit. Wolfschanze 2 on the other hand not at all. If you have played City interactiove FPSes, then you might have noticed how they recycled assets textures, even whole rooms! So most of their games have blended into one grey mess in my head.
The Methadrone Project and Paragraph 78 - yes, heard of those. English version don't exist, so haven't played those. If I'm not mixing something up in my mind now, Paragraph 78 actually somewhat intrigued me back in the day. One thing was that i think it was connected with a russian thriller movie, which had promising trailer... but i never got to watch the movie.
True, one can find some rays of light in those games. I remember having rather liked the 50-60s soviet environment in You Are Empty for an example.
Yeah, TimeShift was made by Saber Interactive, which is headed from States, but development is in Saint-Petersburg. It's actually noteable studio as they are working on this "old Halo trilogy to Xbox 1" now i think. TheiR Serious Sam clone Will Rock is somewhat known as well. Their extremely short (half an hour maybe) FPS Battle Los Angeles disappointed me hugely, as i loved the movie (yeah, i know i must be only one on that

). The latest game for Pc was Inversion I think, but I haven't tried it yet. It wasn't received so well.
I don't know anything about mods though.

I remember my friend rather liked RtCW mods, but I've never even considered those.
Best Russian games for me are.... I think I have to go with Death to Spies series. I like stealth games, and those are made using Hitman engine (what was it called, Glacier?) as well.
I really hope Death to Spies 3 will end up being released! Its been one of my most anticipated games for years! And I loved the demo.
DTS3 have had so rocky development. It was announced by 1C as Ghost of Moscow, but was soon quietly cancelled as 1C big plans in western didn't work out so well (I suppose they didn't realize that games have to have some quality in them to be successful in west

). Haggard Games negotiated the DtS brand and assets back from 1C and independently have pushed on so far. They tried and failed in Indiegogo and Kickstarter (the later was timed extremely bad imho! The Russians had just went to Ukraine and did their thing in Crimea and eastern Ukraine. And after hearing news people see that Russian company now wants money to make violent game about Soviet spies after set after WWII, when russia had just invaded a lot of Europe! To make matters worse, those who made research about company could have found it is situated in Rostov-on-Don, which is just like 100km from Ukraine! Who knows, maybe it had no actual impact on Kickstarter campaign and I'm overthinking, but it still feels to me that they were in wrong place at wrong time when sh1t hit the fan).