I played different versions of OTK Paladin in the last two months and I think this is it now.
To get the last spells you can choose between two of these options:
1. A Libram of Wisdom reduced to 1 or 0 mana
5. Crystology (better use it to draw!)
6. A 1 or 0 mana spell created by Zephrys the Great (very uncommon way to get a combo piece, but it can work)
7. Your starting-coin
I'll try to write a card explanation/guide at +10 upvotes
I hope you enjoy this deck as much as I did so far!