Dom6 Mod Inspector makes it easy to look these spells up but there is no other way but to try them out and understand that EAgartha gets to summon mini-Elementals to hang out at Conjuration 3 but they require a Magical Commanding handler. Umbrals and Penumbrals are also worth considering, but always remember that your access to E3 can let you give really good spell bonuses to your fat but mediocre normal recruits, along with your better units. Always be using that high Earth magic access