Good stuff!
The halflings and "forest" gnomes of my Islands world* have a culture of coastal nomadic pearl divers and fisherfolk, with their cousins who settled down in towns being notable as very friendly and hospitable anarcho-socialists, who have been known to murder every last member of a raiding party and bury them in their fields.
In another part of the world, there is a culture of small folk who train goats as mounts, live in mountainous foothills studded with copses of woods, and ride into battle with lances and shortbows and illusions and raven scouts who've been bred to be able to communicate even with big folk. Some deeply secret religious infraction caused them to sweep into the neighboring Empire of Capet a hundred years ago, wrecking every force that tried to stop them like an avenging tide, murder the sorcerer-regent who was corrupting the child Emperor and turning the empire toward blood magic and ruin, and leave as quickly as they came. The next year they came back as they had before, for trade, as if nothing had happened.
Lastly, there is a culture in that same world that exists across much of the world, that trains from an extreme young age in sword and bow, riding of various mounts, athletics, stealth, and the crafts of fortifications and how to subvert them, and follow a set of deities who patronise those who fight against tyranny and oppression. They are related to the anarcho-socialists mentioned before, and have more halflings than any other ancestry, but there are members of most races amongst them. They have a secret language of handsigns based on ogham staves, and are the source of a lot of legends about small beings who will murder you if you ask for their help but don't pay their price, and the like, even though they aren't as brutal as their legends suggest.