Anki (https://apps.ankiweb.net/) is a powerful, free program that aids with memorization.
The Baltimore Catechisms (https://ankiweb.net/shared/info/1644467154) and Catechism of Pope St. Pius X (https://ankiweb.net/shared/info/670047022) "decks" are available to memorize with Anki.
This is an excellent resource for homeschoolers.