I've been working on Encounter Builder for about a month-and-a-half now. Initially, it was going to just be a way of populating encounters with monsters, treasures and hazards.
But it's grown to suggest thematic elements. Such as suggesting a graveyard, or having the encounter at night under a full moon, if you're fighting undead.
I'm super excited about this. And so far, the Scabard Community has been as well.
I'm starting with monsters.
Here's a screenshot of me filtering the D&D 5e monster list down to just arctic creatures: