I had a hard time to find SteammDB’ like alternatives for GOG

https://steamdb.info/stats/gameratings/

https://steamdb.info/sales/?min_reviews=5000&min_rating=80&min_discount=50

However, I figured out I could use IsThereAnyDeal for GOG: https://isthereanydeal.com/#/filter:gog,&steamcnt/5000/max,&steamperc/80/100,&cut/50/100,&storelow

• Steam review count 5000 – max
• Positive on Steam 80 – 100%
• At least 50% off
• Lowest store price

I open deals in new tabs, check out the game rating (for me it’s 4+) and its all good.