Marriage dates, an major date accomplished by a family member such as college, doctorate, ordination into religious life.
If you know your family anchestry, where did the original family come from, town, dates of immigration, etc.
Don't forget to leave a few block empty for future births, marriages. I would intersort the blank blocks so they are not so obvious and fill them in as needed.
Post the quilt when finished, would love to see it. Have fun.