Since I don't think anybody ever did read my contribution to the Crusader article on the Codewiki, I'm gonna post my spell ideas from there.
Pounce (Charms 2) Not sure if this is possible, but a simulated really fast jump into combat. Perhaps 5-10 turns of Super Swiftness + Flight? Ideally you should be able to move through monster squares as well. This would be quite good to leap in and get out again if you overestimate your abilities. To prevent abuse, it also makes you lose breath and can't be cast if you have breath a bit like Zin's Recitations. Alternatively, pure offence version: check at end of duration whether adjacent to monster. If yes, end effect and force next attack to be a crit. If no, slow or exhaust player.
TrailBlazer (Charms/Fire 3) Create Fire Clouds in your wake for 20-50 turns. Xom already does a similar effect with go forth and redecorate, not to mention Azrael and his flaming trail, so it should be possible. Handy if it can combo with Pounce and Swiftness, for hilarity of leaping out of combat and leaving a fiery wake.
Flash Blade (Charms/Hexes 3) Temporary Confuse brand. Much shorter duration than Mephetic Cloud or Evaporate or Confuse (literally 3-5 turns). But tooled up as a flash of light, so monsters resist based on HD rather than Magic Resistance; and mindless creatures are immune.
Sanctify Weapon (Charms 5) Temporarily grants Holy Wrath Brand (why isn't this available in brands already?).