Google Dataset Search
Google Dataset Search is a search engine for datasets rather than a dataset in its own right. It reads the structured metadata that publishers embed in their pages using the schema.org `Dataset` vocabulary, then folds it into one index that reaches across millions of datasets from thousands of sources: government open-data portals, university repositories, Kaggle, Zenodo, Figshare, national statistics offices, and many more.
Using it is deliberately simple. You type a topic at datasetsearch.research.google.com and get a ranked list, each result carrying a short description, the publishing organisation, a last-updated date, and the available formats where the publisher supplied them. There is no API and no bulk export: this is a discovery layer built for people, so you click through to the original host to download or query anything.
For RAG, treat it as the fastest first move when you know the subject but not the source. Hunting down a niche corpus, say a regional air-quality series or a particular disease registry, is far quicker here than trawling portals one by one. Once you have a shortlist, the real assessment happens on each dataset's own page: licence, access terms, file formats, update cadence, and whether anyone still maintains it.
The caveat to hold onto is that Google indexes whatever metadata a publisher chose to expose, and it does not vet quality, freshness, or licensing. A tidy-looking result can lead to a broken download or a dataset with murky reuse terms, which is why we mark licensing here as 'check source': the licence always lives with the individual dataset, never with the search layer.
Think of it as complementary to a curated catalogue like this one. Dataset Search casts the widest net across the open web; a curated directory trades some of that breadth for vetting, context, and RAG-specific guidance. The two work best together.
Related sources
AWS Data Exchange
A marketplace for finding, subscribing to, and using third-party data inside the AWS cloud. It carries both free open datasets and paid commercial data products, so you can pull licensed data straight into your AWS workflows without setting up separate transfers.
AWS Open Data Registry
A registry of high-value datasets hosted on AWS and made publicly available, covering genomics, geospatial data, climate, satellite imagery, and more. Over 300 PB of data in total, free to access: you pay only for the compute you use to process it.
Datahub.io
A platform for publishing and finding open data packages: datasets bundled with consistent metadata in standardised formats. It hosts curated collections of widely used reference data, from country codes to exchange rates, ready to drop into a pipeline.
Hugging Face Datasets
The largest open hub for machine learning datasets, with well over 100,000 datasets you can search, stream, and version. Many RAG-ready corpora live here, and its Python library lets you pull data straight into a pipeline in a few lines.