The thick stuff, fleece on, the type they use for partial seat covers in automobiles.
I ran into a local who swears by it. He cuts it into strips, the size dependent on the hook and quarry, either for mooching or the bottom, especially for halibut.
He soaks them in processed fish oil stink.
Think about that one. They don't get nibbled off the hook and they undulate in the current with scent attration similar to a natural bait...