Ask Mr. Smarty Plants

As far as we know, there are no plants that fix calcium in the way that leguminous plants fix nitrogen. Calcium isn't as important to plants as nitrogen, phosphorus, and potassium, so no mechanisms have evolved that enable plants to insure its presence in the soil.

If what you're wanting to do is alter an acidic (low pH) soil to make it more calcareous (higher in calcium carbonate) in order to plant species that require a higher pH, our recommendation would be to instead use locally native plants that prefer the region's acidic soils. If the natural calcium carbonate that your soil originally had has been stripped out for some reason, supplementing your soil with lime or applying a top dressing of compost with ground eggshell added can help. Compost from the fallen leaves of locally native plants can also work to restore a regionally appropriate pH balance to your soil.

For plant recommendations, since I don't know what natives you've planted and what the size of your lot is, I'm going to refer you to our regional factpack for the Midwest, the Minnesota Native Plant Society, and the Twin Cities chapter of the Wild Ones for help. The latter two organizations have extensive experience working with native plants and very helpful resources on their websites. They may also be able to help answer questions about your soil.