Regular tinctures do not have high iron levels even if the herbs does. Iron is not extracted effectively by water-alcohol menstuums. The more alcohol, the less soluble it is. I do not know of any research or resources on this topic, although there are lists of herbs that have high iron contents (but again that would be less an issue with a regular tincture), some herbs with high Iron include Ashwagandha, Nettle, Parsley.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4690087/pdf/nutrients-07-05535.pdf
Perhaps Banyan or Organic India might have Indian Madder.