Here are the resources that are included (besides TF2 ones) in a base install. base source engine 2.gcf half-life 2 content.gcf half-life 2 game dialog.gcf source 2007 binaries.gcf source 2007 shared materials.gcf source 2007 shared models.gcf source 2007 shared sounds.gcf source engine.gcf source materials.gcf source models.gcf source sounds.gcf I and another verified this, you don't need HL2 for these resources to show up in TF2 steam installs. However in the goal of fairness and accuracy let's look at what actual content valve decided was appropriate for the style of TF2 that isn't included in the TF2 resources (not including the tool brush textures of course). I used the 'only show used' filter on the decompiled maps and then used the category filters to see what the non-tf ones were. 2Fort: decals/decalindustrialnumber02b and by that logic I can assume any of the industrialnumber decal family are fair game. decals/wood/shot1 Not sure where this is used but I guess it's no big surprised that damage decals are not TF2 specific. metal/metalstair001a This is used extensivly in 2fort, almost all the main stairways are made of this. metal/metalwall003a This is used as the 'skirt' along the 'skybox' wall of the ramp room. metal/metalrail003a This is used as the floor grating above the main fort entrance. (The area where soldiers can rocket jump up through the floor/ceiling and go right around the corner to the main respawn area). That's it for 2Fort, as you can see they made very limited use of HL2 textures. Dustbowl No non-TF2 textures used. Granary metal/metalrail003a This is used again, and this time as a railing. HOWEVER it's only used a a out of bounds prop for a far away object. metal/metalstair001a Also used again. Gravelpit metal/metalstair001a Also used again. Well metal/metalfence004a Used on 3 brushes on a decorative entrance to a off limits area. (beer conveyor belt) Hydro metal/metalstair001a Also used again. THAT'S IT FOLKS! 4 metal detail textures and 2 decals used. So happy mapping with your 4 Valve approved HL2 textures.