When I was a child (back in the early 1960s) the only prayers that were listed in our catechisms, religious instruction books, etc. for the Rosary were the Apostles Creed, the Our Father, Hail Mary, and Glory Be. The mysteries for the day (or all of them if this was to be a fifteen decade rosary) were announced prior to the Our Father at the beginning of each decade.
Other prayers were sometimes inserted depending on the devotion those saying the rosary had to specific apparitions of Mary and those saying the Rosary certainly seemed to consider those prayers to be standard. Some of those prayers may have been adopted by our Popes as favorites such that they have more or less become “standard”.
But to the best of my knowledge there are traditionally only four basic prayers that make up the Rosary.