User-agent: Googlebot
Disallow:

User-agent: AdsBot-Google
Disallow:

User-agent: Googlebot-Image
Disallow:

User-agent: Bingbot
Disallow:

User-agent: Yandex
Disallow:

User-agent: Mail.RU_Bot
Disallow:

User-agent: Mail.RU
Disallow:

#Allow link preview from facebook
User-agent: facebookexternalhit
Allow: /


# Disallow all other bots
User-agent: *
Disallow: /