I don't have an active subscription so there won't be updates to these icon packs for awhile. Most of the icons are still skinned but the new icons Blizzard occasionally adds won't be. Sorry! I'm opening the packs up to patching so if you want to make a patch with the new icons feel free to do so -- I'd appreciate the help.

About
sil_ICON Vanilla Icon Replacement Packs are replacements for Blizzard's 64x64 pixel icon blp files. This particular pack features a black 4 pixel wide border (on your screen it'll be 2 pixels wide if you use standard UI scale). This pack also features a skinned buff consolidation icon and 6 other textures having to do with icons (actionbutton textures and buff textures -- see screenshots).

Install
Extract the zip and place the ICONS and BUTTONS folders into your Interface folder.

Contents
Icon replacement packs like this one should not affect your game's performance. Our icons will load instead of Blizzard's default icons not in addition to. Regardless, you may not need all of your icons skinned and are pressed for room on your hard drive. In such a case you may want to delete some of the BLPs you don't want. Here's a nifty guide to the contents of our ICONS folder:

• BLPs beginning with Achievement_ are used in the Achievement window
• BLPs beginning with INV_ are inventory items seen in your bags or character sheet
• BLPs beginning with Item_ are other loot icons
• BLPs beginning with Ability_Mount_ are mount icons (a few are used for spells)

Those alone account for the majority of the BLPs. If you're looking for specific icons there's an Icon Filename Directory on WoWWiki you can reference.

If you'd like to remove the consolidate buff icon or any of the other modified textures they're in the BUTTONS folder.

AI-Art Users
If you're using AI-Art I recommend you install this after AI-Art since we modify some the the same textures and mine are designed to go with my icon BLPs. For example, when the AI-Art team skined the buff consolidation icon they didn't shrink it down to be the same size as the buff icons like I did (plus it doesn't have the border).

Requests
I'm accepting requests for more vanilla icon replacement packs. Leave them in the comments. Please understand though that batch icon skinning was hard to figure out, wasn't necessarily easy to do and took quite a bit of time.

Links
Other Skins:

sil_ICON:SimpleSquareLT
sil_ICON:SimpleSquareDK
sil_ICON:VeryThin
Clean Icons
Clean Icons - Square
AI-Art Icons

Programs Used:

Gimp 2.6
Blpc
XnView
ImageMagick

Reference:

Wowpedia:WoW Icons