Is there a free way to find trending posts in certain niche on social media?

I'm looking for something like Buzzsumo, but with more searches available.

I used ContentStudio.io which I liked the most, but now they don't have a free plan anymore, only a free trial.

ContentGems, BuzzFeed, RightRelevance, and Trendis are quite good, but I need something better, to see how well is performing latest articles on Facebook.