If you have the full version of NI Kontakt you can get quite a few good and free instruments. Here’s a collection curated by Pluginb Box.
There are lot of ways to manipulate samples in Native Instruments Kontakt sampler. Here are a few inspirations:
Heritage Percussion is a new NI Kontakt FREE instrument. The full version of Kontakt is required to use this instrument. One can add texture and nuance to the track with a FREE collection of 13 heirloom hand percussion instruments: shakers, claves, rattles, djembe and more.
Interesting collection of 5 free instruments for Kontakt from Native Instruments.
Native Instruments offer a ton of sounds (2000) and instruments (Synths, Smaples Instruments) plus an organizer app (Komplete Kontrol) for free. Download here.