Datasets
BIDS compliant data can be found under many of the common neuroimaging data sharing websites/databases. Below are some links to BIDS compliant data. Sourcedata (pre-BIDS) are sometimes also available and these data can be used to test (or to build tutorials) of how source data are converted to BIDS.
Where to find BIDS datasets
Many public repositories for neuroimaging data are accepting (and in some cases requiring) data submitted in BIDS format. Below is a small sample of some main resources for finding BIDS datasets that may be used in your analyses.
OpenNeuro: If you're looking for full data files to run the validator on or simply compare to your own bidsified data try searching here. Datasets here are (by and large) publicly available and conform to BIDS.
The NIMH Data Archive: The NIMH archive hosts many datasets and results that follow BIDS naming structure. There isn't an easy search feature for finding BIDS data as of yet, but larger datasets, such as the Adolescent Brain Cognitive Development (ABCD) study, provide BIDS compliant data.
NITRC: the Neuroimaging Tools & Resources Collaboratory is another resource for finding BIDS compliant datasets. The Neuroimaging Data Repository section provides access to public datasets such as the Autism Brain Imaging Data Exchange (ABIDE) dataset.
Brainhack Western 2018 dataset
These data, compiled at the Brainhack Western 2018 event can be used to test or create BIDS apps. An example of sourcedata ds001 (non-BIDS compliant NIfTi files) and raw data ds001_BIDS converted to BIDS format are provided.
Mother of unification studies
A 204-subject multimodal (MEG, MRI, fMRI) dataset to study language processing.
BIDS examples with empty raw data files
BIDS examples datasets contain empty (example) raw data files and can assist you in converting your own dataset into a BIDS compliant dataset, or to run some tests with your code...