Hi! A lot of people pointed out above a problem with your team- you don't really have many pokemon that can actually use
the speed loss of your opponent. Your team is also very pursuit weak, yet it still doesn't have any powerful attackers, nor any powerful walls. Your team is also extremely weak to Thundurus-T, who can't be paralyzed and just wrecks everyone with Specs SE moves. Thunder Wave should be used to support your team; it shouldn't be the main strategy. In order to achieve this goal, there are a few things I think you need to change.
Your team is really weak to Tyranitar- not a single member on your team resists its attacks, and Celebi, Victini, and Starmie are all OHKO'd by Pursuit. Dragonite and Haxorus fall to repeated Stone Edges, while Jirachi falls to defense drops after multiple Crunches. Ttar doesn't care about paralysis either- it's already slower than every member of your team. In order to counter it, I suggest you replace Starmie with Offensive Donphan- it takes nothing from Ttar's attacks, and can reply with a STAB OHKO EQ. Donphan can also spin for Dragonite, whisking away Stealth Rock that would break its Multiscale. Paralysis also helps Donphan a lot, whose base 50 speed is pretty fast when the opponents whole team is paralyzed.
Donphan @ Leftovers
252 HP / 252 Atk / 4 Def
Donphan can spin and set rocks up- it also hits ground types hard with Ice Shard. It's a perfect member for the team.
Speaking of Ground types, sturdy ones such as Gliscor or Mamoswine will be very problematic, especially because all of them are immune to paralysis. That's why Jirachi should be given Body Slam
instead of Thunder Wave- so you can hit those Ground types and still paralyze them. Body Slam also hits Jolteon and Thundurus-T, crippling them for the rest of the match. Now that you have Donphan to set rocks, Jirachi should use Fire Punch
instead of Stealth Rock- so you can hit Magnezone and Scizor hard. I think your Celebi's moveset also needs some tweaking- I would suggest Uturn and Perish Song
instead of Recover and Hidden Power Fire. Celebi's primary goal should be to spread status- and using Perish Song to force the opponent out allows you to paralyze more pokemon. U-turn is great for scouting, which is definitely something you'd take advantage of. It also erases SpA drops from Leaf Storm while still being able to deal some damage.
Victini also seems to be a pretty weak link in your team. It doesn't provide any helpful coverage that is not already taken care of, and only adds to your team's weakness to Pursuit and ground types. Since you also have two Dragons in your team, I would recommend Magnezone
to replace Victini.
Magnezone @ Air Balloon
36 HP / 252 SpA / 220 Spe
~Hidden Power Fire
Magnezone traps and KOs Scizor and other Steel types that will give your team a lot of trouble. Its low speed means that it will also benefit greatly from paralysis support. With Magnezone and two Dragons, you will form an effective core.
Nice team, and good luck!