Picture Books
Mary, by Brian Wildsmith, Oxford Uni press. The True Cross, and The Easter Story and Saint Francis, by the same author, also OUP
Unicorns! Unicorns!, by Geraldine McCaughrean, illus. Sophie Windham
The story of the Creation, illus Jane Ray, Orchard Books
Lives and Legends of the Saints, Carole Armstrong, with illustrations from great art - so Fra Angelico, Caravaggio, Ingres...
Saints and Angels, Clare Llewellyn
On Noah's ark, Jan Brett - and also her Who's That Knocking on Christmas Eve?
Reading 8-12
The Ignatius series of saints' lives for children - ok, saccharine, and most date from the 1950s, but my dd adored them.
Most RC kids make their first communion between 6 and 10. MY dd made hers at 6 - Pius X said the test was if the child is old enough to tell the difference between ordinary bread and the eucharist.
For 10+ kids you should really look at proper theology in the runup to Confirmation. Boys often like the English martyrs; if ds is a good reader try Evelyn Waugh's life of Edmund Campion.
Family Catholic customs
A book of feasts and seasons, Joanna Bogle
The Catholic Home, Meredith Gould
A Continual feast, by Evelyn Vitz - includes recipes!
I use apps a LOT, and two of the best are iPieta - just about every prayer you could want, every major writing, plus a FULL catholic bible and missal for just 3 quid or so, and the other, more expensive but cheap compared with the books, is Universalis, all of the monastic hours for every day, plus the saint of the day and a bit about his or her life. You can also get rosary apps, Divine Mercy apps, and confession apps where you can record your sins, all ready; they are password lockable and some new confessors might find them helpful. You can also get a lovely app which lets you light a virtual candle to any one of a number of saints.
I hope this helps...