1. Games Workshop
GW's Empire halflings need no introduction obviously. The range used to include halfling bowmen, spearmen and swordsmen as well as a hot pot catapult.
http://www.games-workshop.com/
2. WK Halflings
Not a commercial range, but my personal privately commissioned (and growing) landsknecht dwarf, goblin and now also halfling range that you can find to the left of this post. :) These are slightly taller and thinner than your regular potbellied halfling. There are halflings with spears, halberds, swords, crossbows, handguns, command and some wizards.
3. The Battleforge
Uk-based manufacturer of characterful fantasy figures, including some halflings with renaissance influences.
Website: http://www.thebattleforge.co.uk/
4. Black Hat Miniatures
Black Hat took over the small fantasy range from Crusader Miniatures. They are not full-on landsknecht halflings, but have a similar vibe to the old GW ones. The range includes command, spears, archers, slingers, and swords.
Website: http://www.blackhat.co.uk/