That’s a great question! At this time, it is not possible to query all of the files related to a specific board, but you can query a specific board and a certain number of items, returning their assets with ID and public_url. For example:
query {
boards (ids:391141870) {
items (limit: 100) {
id
assets {
id
public_url
}
}
}
}
This can be quite a costly query complexity-wise, so I recommend limiting the numebr of items you return at a time.