My biggest complaint with the default beard in the game..... is the mustache.  Because of this, I looked for some beautiful beard mods -- and ended up finding $ereg@'s "Hairworks beard Fix" -- initially got it for the fuller mustache, but ended up loving the fuller, high res beard.  However, I missed the darker, mixed color vanilla beard; so I mixed the two and created an add-on mod to darken up his beautifully made mod for anyone like me.

-!!!- As stated earlier, this mod does NOT replace his mod; to use this you need to download and install his mod, then give this mod priority -!!!-

Versions 1 and 2 of this mod were made and tested in private; I am torn between Version 3 and 4 so I decided to upload both.
Version 3:  Slightly whiter and fuller (in relation to V4)
Version 4:  Darker and patchier, but more realistic (in relation to V3)
NEW Version 5:  Darkest, but not as patchy (in relation to V4)

INSTALLATION:
- Download and install $ereg@'s "Growing Long Beard" mod here: https://www.nexusmods.com/witcher3/mods/3149?tab=description
- Download and drop the "modFullerBeardFixV*" to the "mods" folder in your Witcher 3 directory.
- Using Mod Merger or whatever tool you use, give "modFullerBeardFixV*" priority.

My Other Mods / Tools:

• Yrden Griffin Bonus (No Armor Required)
• THE Shirt -- Ultra Gamer Armor Overhaul
• Universal Grandmaster Bonuses (All Bonuses - No Armor Required)
• Master Horse Equipment
• Combat HUD
• Recursive String Parser (PowerShell Tool)
• DEEN -- W3strings Decoding and Encoding (PowerShell Tool)
• Combat Hud Redux
• Universal Set Bonuses Redux
  

In the screenshots I am using Phoenix Lighting Mod, Reshade.me (FXAA.fx, qUINT_mxao.fx, Colourfulness.fx -- all with tweaked settings), HQ Faces, Hairworks on everything but Geralt, Geralt hair LOD + Whiter Hair mod (Hair - Increase LOD distance shift), as well as a beard LOD mod.