Loop / iterate over KV keys in Cloudflare workers. In this example, I limited the output for the list request to 2 on purpose to check if everything works as expected.

async function listAll() {
  // list all keys from a given NAMESPACE,
  // in this example the output is limited to two on purpose
  // to make it paginate. The default is 1000
  let entries = await NAMESPACE.list({ limit: 2, type: 'json' })

  // get cursor, if returned
  let cursor = entries.cursor

  let loop = []

  // get entries from first call above
  let output = { ...entries.keys }

  // as long as `entries.list_complete` is false, loop over the next block
  while (!entries.list_complete) {
    let next_value = await NAMESPACE.list({ cursor: cursor, limit: 2, type: 'json' })
    // update `entries.list_complete` to break the loop
    // as soon as we've got all keys
    entries.list_complete = next_value.list_complete
    // update cursor for the next call
    cursor = next_value.cursor
  // merge keys from very first output with all the subsequent keys
  // from paginated calls
  output = { ...output, ...loop }

  return output

Cloudflare workers KV docs