OK, I don't pour any plastics, so not up to date on what might be available. I know that Hilts Molds used to offer jig molds, with a melting pot as a kit, but the type was limited. It was usually a round head jig mold, but used to be the jig styles were quite limited anyway.
Now, there's a lot of different jig types and many, many plastic types too, so wouldn't be practical to make kits that might cover them all.
I have also seen them on places like Amazon, but not usually brands I was familiar with.
Perhaps the folks with Do It will read this and can tell you if they have anything available.
Otherwise, perhaps contact some of the retail sellers, such as Zeiner's Tackle in KS, Barlow's Tackle in TX, or Rock Island Sports in NY and ask them if they have kits or would be willing to assemble one for you, if you have an idea of what you might want to pour.
Ben Zeiner with Zeiner's, Jon Barlow with Barlow's Tackle, and Mr. Bill who owns Rock Island Sports have all been good for me to deal with and have helped me out a few times, although I have not looked for kits. It was usually I had bought a mold or molds, and asked if they could get me the hooks &/or other components I needed. It didn't necessarily save me much, except for time & extra shipping costs.
I would think the folks with Do It might be able to do the same.
