Does this apply Does this apply to all fossils?
... Other good stuff...
And here in the United States at least, there are other considerations. If I find a T-Rex on my property it belongs to me. i.e. It's just as much my property as any other rock I dig out of the ground. I'm free to do with it whatever I want.
To start, with: no, this absolutely doesn't apply to all fossils. Some things are relatively plentiful, like petrified wood. But others are extremely rare. There are some ancient life forms that only have single specimens. So there's a huge range here. That's why I was asking if anyone knows about the rarity of T-rex fossils, because I'm not an expert. But I do think they're much more rare than people think. Most of the dino skeletons you see in museums are casting, not actual fossils. I linked to Sue before, and that's essentially a unique find. So...

I'd love information, but from someone who isn't selling or buying it.
The other main thing to think about here is mass production. Nobody will notice or care much if you find a rock on your property and make a d20 out of it (unless it's uranium or something, it guess). But this Kickstarter is potentially making thousands of dice between the carved and cast sets, plus whatever their recast bones uses. Is that a lot of T-rex fossil material to consume? Will the next Kickstarter use ten times as much? Does that matter? I don't know! But I know I can't ask the people selling it to give me a straight answer.
And really, my questions are about a bigger picture than backyard art projects. The world doesn't end because one rhino is killed, but we don't allow selling rhino horns because free trade leads to all rhinos being killed. Ditto for ivory, and plenty of other materials. Controlling the market for certain products is responsible capitalism. People love to complain about the evils of late stage capitalism, especially in threads about AI. But it's not like capitalism or free markets are an absolute. And it would be great if we could have a simple conversation about things like this before all the fossils are destroyed rather than after. An ounce of prevention, a pound of cure, and all that.