Paracord wraps are very lightweight.
Handles are pretty small. Unless there are extreme cases with which I'm not familiar, the weight difference between two identical handles made of various micartas, G10, bone, carbon fiber etc will be measured in a couple/few grams... usually not enough to have a major impact on balance or overall weight. Different woods can vary even more, but again we're not talking several ounces. I suspect that in most cases you would feel a greater difference in knives between using three 5/16" bolts, and two 1/4" bolts, than between types of micarta or even G10 vs. carbon fiber.
I don't have actual weight measurements in front of me, but neoprene is pretty light, if you also happen to like a soft/slightly cushy and very "grippy" handle. It's not pretty, but it makes for a very comfortable handle.
Honestly, I just don't worry about handle material weight very much. I find it a lot more effective to work on the steel to deal with weight/balance (by tapering the tang, skeletonizing it, etc) and choose handle material based on durability and appearance.