I'm nursing and pregnant. I don't take extra iron.
This is what I take for supplements:
3 capsules Thorne's Basic Prenatal
2000 mg Vitamin C
2000 iu Vitamin D3
200 mcg Selenium
1 capsule Vital Nutrients B6+B Complex
1000 mg MSM
1 capsule Vital Nutrients Adrenal Support
1 tsp Nordic Naturals Arctic-D CLO (not consistent)
Papaya enzymes, as needed for reflux
I may be adding in a few more capsules of Adrenal Support (I'm supposed to be on 4) here soon as well as a Cal/Mag supp.
I'm under the care of a ND, who has okayed the use of these for me. I have a few health issues which we're working on (including hypothyroidism, for which I also take Armour thyroid), so YMMV.
The concern, I believe, when it comes to nursing is that some things are concentrated in breastmilk and some nutrients can facilitate the release of toxins into the bloodstream (and therefor the milk). I could be wrong, but that is my understanding.