Zing-it or Lash-it (throw cord for arbourists) is stupid strong and can be spliced. its coated to hold knots better, but is also more resistant to tangles. you can even make adjustable slices (whoopie-slings) for tensioning tarps and such
My hands down fave right now is 3mm static climbers accessory cord. its got a break load of around 180kg (395 lb), depending on maker. Its thin, light, holds knots really well. they will lock down, so bowlines are best if you want to ever undo them, but a fishermans will be set for good. Its also thick enough to handle with cold hands, 2mm is just a little too thin for that, but I do like it as well. 4mm gets you up to 400Kg and is really good stuff. I don't bother with paracord anymore unless its totally unimportant and sacrificial. Yes you will spend a bit per yard on it, but it still cheaper than kevlar or dyneema, and it gets the job done. I won't hang my life on anything less than 6mm, but I'm a cautious guy.