Thanks again to Baytor for compilation of these site lists

Blood 2

Updated Blood 2 demo (36 MB, requires DirectX 6) 

Planet Quake Mirror Site 
Planet Quake International Site 
Blood Shack Mirror Site 

Upgrade Blood 2 demo patch (2.7 MB) 
Planet Quake Mirror Site 

The Blood 2 version 1.0 to 1.1 Patch  

Planet Quake Mirror 
Blood Shack Mirror 

Blood

Important Note: If you have the European version of Blood, do not download any patches. The US patches will not work with the UK 1.02 version of Blood.  

3DFX Patch (Alpha Version)

Important Note: If you have One Unit Whole Blood, do not use these patches 

Plasma Pak 3DFX Patch 
Blood Registered 1.11 to 1.20 3DFX Patch 
Blood Registered 1.0 to 1.20 3DFX Patch 

Registered Version

Version 1.1 to 1.11 Patch 
Version 1.0 to 1.11 Patch 
Version 1.02 to 1.1 Patch 

Plasma Pak

Update Blood Registered Plasma Pak to 1.11 
 

Patch for Bloodless Version 1.0

Patch censored 1.0 to uncensored 1.0 

Cryptic Passage

Download Cryptic Passage Demo 
 

Cryptic Passage Patches

CPPATCH.ZIP -- This should fix almost any problem you may be experiencing with Cryptic Passage, including crashing on Pentium II, missing Windows directory, and installing to a version of Blood higher than 1.02 

CPMULTI.ZIP -- If you're having trouble getting multi-player to work, this patch should solve your problem. 

Blood Shareware

Download Shareware version 1.11 (17 MB) 

Blood Shareware Patches

Update Internet Shareware 1.1 to 1.11 
Update CD Shareware 1.1 to 1.11 
Update CD Shareware .99B to 1.11

Blood TC's (Total Conversions)

Bloodlines TC

"The demo for this one is out. The Bloodlines team are still pulling together new art and sounds, though all the levels have been build (just tweaking now). The full project will be four episodes long."  

As a side note, Control-Z designed and built "The Cathedral" level in this TC.

Download the demo. 
 

Banzai addon

"This one is an entire episode an episode long. I haven't played too much of it yet, but the first couple of levels are pretty solid. There's a really bad-ass dam level that puts the one in the original to shame." Review by Baytor
Download it here. 

Gods

"A small TC, but still worth a look, especially if you're into solving puzzles. The small plane level that opens it just about worth the the 2 Mb download." Review by Baytor
Download it here. 
 

Blood Archives 

Not an add-on, but the largest source of Blood 1 maps on the internet. 

Blood Links

Blood Supersite (PCGAME.COM)
Hank's Blood Page
Michco's Ultimate Blood Mapedit Suite