I assume that you already receive the Adherent staff by completing the Magic Range. If not, you can get another one. However, you need Mirabella/Xenoa as they are the only 2 wives that have weapon slot. Remember to upgrade it to Archmage's staff later.
Other than that, I can only recall 2 fixed items that benefit any blasting mage. The first one is the Old Skull (+3 Intellect, +10 Mana). You get it in the Magic Valley in Ellinia from the shaman who summoned the boss turtle earlier. There is an option for you to fight the shaman but either way you get the artifact.
Another one is the dragon cloak (grants 15% power to your damaging spell). You will get it by completing the Seven form of Haas which is only available later in the game.
For more information about wives/babies,
read this thread. I am really not a big fan of babies, especially for Feanora. I always want to strangle her to death when the newly born baby increases the scroll capacity.