We are (slowly) adding more spells to this website. I will try to add one a day until our spell book is complete.
Casting magic is one of those things where you always learn and can always improve. For example, let's say you try a luck spell as the first spell you ever cast. You may find a minor improvement in your luck but not a drastic one, after all this is your first spell.
In a couple years from now, after you have been practicing magic, you may still be casting luck spells and you will still see your luck improve a little each time, but still no drastic change.
And you may think that really your casting has not improved, since your luck only gets a little bit better. But when you look back and compare the spell you casted the first time versus the one you casted after years of practice there is a great, great difference.
So to answer your question, any spell on the website is a good spell to get started in. Even though many may warn of bad concequences, you must remember that the bad can only be as powerful as the good if cast correctly. So if you are new at magic and your 'good luck' spell backfires, at most you will stub your toe on the way out the door, because you aren't that powerful at casting yet, the bad will not be powerful either.