If you're looking for an AI-powered music sampling service that lets you search for samples by typing natural language descriptions, TwoShot is a good choice. It's got more than 200,000 samples, and an AI sample generation tool lets you request specific samples based on your creative direction. A natural language search engine lets you find samples by typing text prompts. And it comes with an audio sampler plugin for several digital audio workstations and an online jam studio for turning ideas into songs as fast as possible.
Another good option is Samplab, which is geared for polyphonic audio sample editing. It doesn't offer natural language search directly, but it offers sophisticated sample editing abilities and a relatively approachable interface that's available as a VST3 and AU plugin or desktop app. That means you can use it in your favorite digital audio workstation.
If you want to tap into generative abilities, Soundry AI offers text-to-sound abilities and unlimited sample packs. It doesn't specifically mention natural language search, but you can generate sound samples based on text prompts, which could be a useful way to find samples by typing a description.
Last, Mubert offers an all-purpose AI music generation service with a range of tools and services. It doesn't specifically offer natural language search, but it can generate tracks on the fly and has a large library of samples you can use for music, podcasts, streaming and video. It's a good all-purpose option for getting high-quality audio.