Would be nice if radioactive items had a radioactivity metric in their tooltip, so you could tell how dangerous they are. This would help in calculating how much investment you need in radioactivity absorbtion for your armor.

There's new custom tooltip functionality in Factorio 2.0.60 you could look at for this.
For inspiration on how: https://mods.factorio.com/mod/more-descriptions

Definitely something I will look into. Will make it optional as it will require a mod as an addon.

Had a look at implementing additional tooltips using the mod you have mentioned however there seems to be no current method to add custom tooltips using the mod.

I have made a thread requesting some form of API that my mod can use to add custom tooltips so waiting for a response on that.

If not, I'll just make my own implementation adding it. Depending on how adding custom tooltips work I might make a separate mod that other mods can use to add custom tooltips, but it entirely depends on how Factorio handles tooltip creation.

It doesn't have any API, it's just a mod that also adds additional tooltip info, which is what I meant by looking at it. You don't need another mod to do it yourself.

I understand now. In my mind I thought it was something more than it actually was and overcomplicated it in my head. I'll have a look and see whether it is possible in the control stage as I also want to give the ability for modded items as well to display the radiation level.

Now implemented in Version 0.10.2