In addition to the stones already suggested
stones to work with for promoting fertility include
quartz manifestation crystals crystals with "babies". Family clusters are supportive in crystal grids etc.
Crystals that are good for balancing the hormones, improving the blood circulation, encouraging relaxation and helping to ensure a healthy pregnancy include Rose quartz, moonstone, bloodstone, unakite, rhodonite and quartz crystal .
There are many choices of stone which can be carried or put in grids for promoting fertility. What stone makes best choice will depend on the specific situation. Use your intuition and look around to see what stones are making themselves available.
The best fertility stones I've encountered placed themselves /were found on the street. One is a whitish pinkish stone that is shaped rather like a pregnant woman but is not identifiable as any specific rock or mineral. Another was a piece of San Francisco Jade.
Traditional stones for fertility include holey stones, egg shaped stones, rose quartz, carnilian, Mexican fire opal, green and orange calcite, moonstone chryoprase, red coral, garnet, shiva lingum, smoky quartz and Dolomite, Manifestation crystals and abundance clusters of quartz.
Not Crystal healing but another fertility calling practice is to hang lead crystal in the double drop cut in a sunny window. there is also an ancient tradition of carved stone figures in many cultures as fertility talisman.