Searched and didn't find any topic like this, can be extremely useful if kept updated 🙂 Anyhow, I'll start off with a few I've found.
http://store.steampowered.com/app/11170/
Pre-Purchase King's Bounty: Crossworlds before September 17th and receive a FREE copy of King's Bounty: The Legend for yourself or gift it a friend.
http://store.steampowered.com/app/63910/
http://www.gog.com/en/page/i_love_paypal
activison strategy game sale
http://www.gog.com/en/promo/activision_strategies
Steam:
Blood Bowl 75% off this weekendhttp://store.steampowered.com/app/11170/
Pre-Purchase King's Bounty: Crossworlds before September 17th and receive a FREE copy of King's Bounty: The Legend for yourself or gift it a friend.
http://store.steampowered.com/app/63910/
Gog.com:
25% off select games when purchased through paypalhttp://www.gog.com/en/page/i_love_paypal
activison strategy game sale
http://www.gog.com/en/promo/activision_strategies
