Listing possible supplements that may be carcinogenic at some levels doesn't address the expanded information that reveals the flaws in the study in the original post.
The study was not flawed as such, but Shanti did a nice job analysing the study, and pointed out that it was just too small to reach statistical significance. That means the finding of a carcinogenic effect of nicotinamide riboside could be correct, but it the finding might also be due to random chance. Only a larger study can address this, ie, a study which uses more mice.
It is normal in research to conduct these small-scale studies first, and then if an effect is found, to conduct a larger study to confirm or refute. If a larger study is performed, then we may have more info.
However, the brain metastasis part of the study was statistically significant. So NR may well promote triple negative breast cancer metastasis to the brain.
I listed the known carcinogenic vitamins just to show that supplements can promote cancer. Some people may think that supplements are always benign, but like everything, they can have their downside. It's better to be informed of these downsides than not.
I take high dose selenium daily, and it does concern me that whilst selenium is protective against many cancers, it promotes the more aggressive forms of prostate cancer. You have about double the risk of dying from these aggressive prostate cancers if you are taking higher doses of selenium. But selenium has such a good effect on my ME/CFS symptoms that I have to balance this risk against the benefits I get for my ME/CFS.