(Let's stay on topic guys and not spam)
This is a very hard choice. The Permian was when Synsapsids first started getting big asf and diversify, which a lot of cool giant carnivores like Anteosaurus, and large herbivores like the Moschops(which apparently might have lived a lifestyle similar to hippos). On the other hand you have the Triassic, and it is so interesting and the animals are just straight up weird.