Free Drums

Drum Sets

DrumMic'a (VSTi) Amazing drumset with midi patterns, but you have to register in German  This site walks you through it. It's a pain, but likely the best free instrument in existence.

SM Drums (Kontakt, TX16WX, SFZ, Reaper)
SmithULTD / Evil Dragon Kontakt Drums (Kontakt)
Scott Drums (Kontakt)
Quartertone Drums (Kontakt)
MT Power Drum Kit (VST) note requires free registration
Salamander Drumkit (SFZ) Download the samples. Then you add the sfz files as instructed.
Big Mono (Kontakt)
GSCW Drumkit (Kontakt) plus SFZ mappings
Open Source Drumkit (SFZ)
Free Jazz Funk Drum Sample Library (Kontakt & SFZ) Get the SFZ files here.
MF Natural Drumset (SFZ)
SonicCulture Brush Kit (Kontakt)
NS Kit 7 (SFZ)
Easyrider and RuffRider (Kontakt & SFZ)
Plutonic 1965 Ludwig Super Classic Drums  (Kontakt & Maschine)
Room Boom Drums (Kontakt)
Sam Greene Drum Kit (EXS24 can import to Kontakt)
Pettinhouse Kits (Kontakt Battery & SF)
Retro Drum Kit (Kontakt)
Waves Factory Old Tape Drums (Kontakt)
DSK DrumZ AcoustiK (VSTi)
Real Snare (SFZ) Snare & Kick 
Control Centre Olympic Floor Tom (Live) & Darongo (Loops)

Electronic Drums

Vintage Drum Elements (VST)
Da Real 110 (Kontakt, SFZ)
DrumBoxx (VSTi)
EDX80 (VSTi)
GTG DPC 3 (VSTi)
Dr Fusion 1 & 2 (VSTi)
ERS Drums (VSTi)
Impaktor (VSTi)
Gameboy Drumkit (Kontakt)
DSK DrumZ MachineZ (VSTi)
DSK DrumZ 8bitZ (VSTi)
DSK Synth Drums (VSTi)
DSK Mini DrumZ 2 (VSTi)
DSK DrumZ BeatVoiZe (VSTi)
Pettinhouse Kits (Kontakt Battery & SF)

Free Bass Guitars

Continuing the band instruments with the big basses. As usual Pettinhouse has a very nice free instrument. The Project 16 Bass that he allowed me to Kontakt sounds good and has lots of articulations (I'm biased). Karoryfer's Pasta Bass is their best ever and awesome!

Pasta Bass (SFZ)
Direct Bass 2.0 (Kontakt)
Project 16 Bass V2 (Kontakt)
Flame Studios (SF2) or bigcat versions (Kontakt)
FS Washburn Acoustic Bass Guitar (SF2)
FS Ibanez Electric Bass Guitar (SF2)
FS Yamaha Electric Bass Guitar (SF2)
Rickenbacker 4001 electric bass (SFZ)
Control Centre Rickenbacker 4001 (Live)
Project16 Rick 4001 Bass (VSTi)
GrowlyBass (SFZ)
SwagBass (SFZ)
FashionBass (SFZ)
XMas Bass (Kontakt)
8 MSLP Basses (Kontakt)
Ergo Electric Upright Bass (SFZ)
Precission E-Bass (SFZ)
DSK BassZ (VSTi)
4 Front Bass (VSTi)
OM Bass 2 (VSTi)
Naturally Decaying Bass (SFZ)
Free Bass (SFZ) 
Tubed Bass (SFZ)