Immediately I matched on those top two, for just about the same reasons. I was particularly impressed with what the Grimlock culture shows you can do with the Culture slot as a building block for a character. Stoic Orc was probably my 6th position, just below the cut, and Tunnel Halfling is right afterwards, those are some my top ones that have a particular heritage flair associated.
I picked Dragoncult, again because I really like specificity of its mechanics, it gives you a really unique widget to play with that grounds you in a specific place to have those abilities. In particular I like the idea of a character escaping or leaving a dragon cult behind, and still having that mark and power left to call them out.
I picked Eladrin, because honestly I've never liked the presentation of Eladrin in their 4e roots. Splitting elves into two distinct species always struck me as weird, and it seemed very strange to present a player race that was theoretically from the weird faerie realms, but not to give it any grounding in the weird norms of that place, nor enough power to compete with the rest of the fey. Eladrin as a culture however, squares the circle nicely and really makes me more excited about such characters.
And then finally I picked Bloodmarked, because I really liked the Zeitgeist take on gnolls, and because I thought the mechanics are very solid. It's a really good example of distilling adventuring relevant abilities from a social background, while making them distinct and not entirely passive abilities that fade alongside class stuff.