While not a "one-click" solution, modern developers often recommend jBridge or simply using Kontakt's built-in "Bank" features. Passmark Burnintest Portable Exclusive You Can Have
Kontakt Library Creator (KLC) is a lightweight, third-party utility designed to create user libraries for Native Instruments Kontakt. For years, it was the go-to free solution for users who wanted to organize their one-shot samples into a professional-looking library interface without spending hundreds of dollars on developer tools. Sicflics - 3.79.94.248
However, the closest modern equivalent for easy library creation is (a newer community tool) or utilizing Plogue sforzando (which is free and creates SFZ files that Kontakt can sometimes read, though natively KLC is better for NKI).