Add Thunder. I know it does not have high accuracy but the pros outweigh the cons. The high power is enough to make up for the lower accuracy. Thunder has 10pp unlike Fire Blast and Blizzard. If you also have Kyogre or any Pokemon on your team that uses Rain Dance, Thunder has 100% accuracy plus a 25% chance to break through Protect and Detect. Or, you can even give your Jirachi Rain Dance in exchange for Swift, seeing as Rain Dance would also make Water Pulse more powerful. However, let's get back to Thunder. Thunder can also attack Pokemon using Fly, a small bonus seeing as Fly is not that popular around the competitive battling scene, but it shows up from time to time. Finally, the main point for choosing Thunder: Serene Grace. Jirachi's ability doubles the chance of your moves having a secondary effect. Thunder already has a 30% chance to paralyze, but with Serene Grace, it has a whopping 60% chance to paralyze.