If you're looking for some excellent new instruments and that unemployment money hasn't come yet then you have to check out Pianobook. Started by one of the founders of Spitfire Audio, makers of the fabulous LABS, Pianobook features a collection of 295-and-growing, sample-based instruments, recorded by some of the best audio engineers, as well as some more novice but passionate sample enthusiasts. The best thing is that they're all free to download.
Despite the name, it's not all pianos. There are drums, wind instruments, horns, guitars, strings, choirs, analog synths and even some strange things you wouldn't expect. Formats vary from Kontakt, to EXS24, to SFZ, and to SF2. However, Kontakt seems to be the most popular and they should work in the free Kontakt Player. Some of these instruments are on par with, or better than, some of the most costly commercial Kontakt libraries. An appropriate starting point I can suggest is the Quarantine Piano.
The ever expanding Spitfire Audio plugin, LABS, that I mentioned earlier is another free blessing from the audio gods. The "Soft Piano" and the "Rowdy Brass" are two LABS components that I use often. Between LABS and Pianobook you should be mostly set on natural instruments like piano or violin.... for awhile at least. If you haven't already, make sure to visit our free downloads section HERE.