The USCCB has a beautiful blessing of parents after a miscarriage or stillbirth that I refer to quite often.
I wrote a Bereavement Novena for anyone to pray on behalf of loss parents and families.
The Archdiocese of St. Louis has a lovely Naming and Commendation Rite specifically designed for perinatal loss.
Becca at Delightful Inklings wrote a beautiful prayer for loss siblings that I highly recommend.