Well, those Zygote ones you linked certainly look impressive. They dont directly say what their prices are, so I assume probably very expensive.
Depending on what your use is, potentially these ones from CGTrader would work? https://www.cgtrader.com/3d-models/character/anatomy/male-anatomy-model-with-internal-organs-with-4k-textures
They are fairly cheap.
Blendswap is free, and often not super great, but there are some good things on there. For instance, this skull is very nice. https://www.blendswap.com/blend/20934 and this heart (to my non medical expert eyes) looks pretty good. https://www.blendswap.com/blend/12579
I hope I helped. To a certain extent the best of anything is subjective, but I’m sure you want the most objectively accurate things you can find. Zygote seems like a really good option. But of course, I’m not a doctor, or a person who typically uses anyone elses models.