These Data Explorer queries can help in these cases.
1ª List of users per login with Facebook
WITH target_user_ids AS (
SELECT id
FROM users
WHERE staged = false
AND active = true
AND last_seen_at IS NOT NULL)
SELECT
provider_name,
user_id,
info->>'name' name_user,
info->>'email' email_user,
info->>'image' image_user
FROM user_associated_accounts ua
WHERE user_id IN (SELECT id FROM target_user_ids)
AND provider_name = 'facebook'
WITH target_user_ids AS (
SELECT id
FROM users
WHERE staged = false
AND active = true
AND last_seen_at IS NOT NULL)
SELECT
provider_name,
user_id,
info->>'name' AS name,
info->>'email' AS email,
info->>'image' AS image
FROM user_associated_accounts ua
WHERE user_id IN (SELECT id FROM target_user_ids)
WITH target_user_ids AS (
SELECT id
FROM users
WHERE staged = false
AND active = true
AND last_seen_at IS NOT NULL)
SELECT
provider_name,
COUNT(user_id) AS qtd
FROM user_associated_accounts ua
WHERE user_id IN (SELECT id FROM target_user_ids)
GROUP BY provider_name
UNION
SELECT
'github',
COUNT(user_id)
FROM github_user_infos
WHERE user_id IN (SELECT id FROM target_user_ids)
ORDER BY provider_name