If you can't find the specific older mod you're after, these modern "standalone" mods are currently the most popular way to experience a more intense, "Black Stalker"-style Zone:
Finding the "Chernyi Stalker" (Black Stalker) mod for the S.T.A.L.K.E.R. series can be tricky because several different mods use that name or feature the character prominently. mod chernyi stalker skachat torrent
If you are looking for the classic "Black Stalker" mod or similar story-driven overhauls, you can usually find them on major community hubs: If you can't find the specific older mod