IFP - Celestia and/or Luna... ill admit its mostly celestia. This is one of my favorites.

Ideas for Projects. If you see anything you like, take it and make it your own. Most of these have probably been done in some way or another, but they might give you a different idea while reading them or you might decide to use it anyway. Just because it's been done before doesnt mean you shouldn't do it. Yours will be different im sure..

11. Someone has stolen the SUN!... at least... most of it.

38. Batponies and changelings both know what it's like to be ostracized and hunted. Celestia tried to find them for years to make up for what she did after Luna's banishment.

42. A secret organization seeks to overthrow Celestia for being too nice to criminals, villains, and non-ponies. They set out to frame her and all her allies. 

49. Celestia is losing it, just like luna over a thousand years ago. Celestia had 3 contingencies hidden in her regalia. The first will try to remind her what's at stake. The second would try to contain her long enough for the elements to be used on her. If that fails, the third WILL kill her. The problem is no one knows once Daybreaker gets free, Celestia is gone forever, not even Daybreaker herself.

51. Without the elements, the only way to stop Daybreaker, was for Celestia to merge with her and hope for the best. Dawn is a very loving and accepting being... until you piss her off. She wants to rule. Celestia got to rule for 2 thousand years, NEW DAWN, or just Dawn for short, wants 1 or 2 for herself. She sets off to find a tyrant to defeat, and a kingdom to claim. She will take it with fires of rage and retribution but will rule and protect with the fires of love.

60. A changeling tries to help stop a plot to kill Celestia. Too bad no one believes him/her. Now they are fighting both sides to prevail.

73. Celestia has nightmares more and more often, ones that luna can't enter. It is starting to wear on her. One day she doesn’t wake. They have to strap her to a bead and feed her with an IV until they can figure out how to save her. Can they save her while there is still something left to save, both physically and mentally?

74. Unrelated to 73. Luna has to put together a team to fight the things that go bump in the night. Both in the real world and to help in the dream realm. Mostly in the real world though, because most ponies don’t know it, but some bad dreams are caused by the very REAL things.

75. Daybreaker and nightmare moon get separated from Celestia and luna, along with half their power. You may think that a bad thing, but Celestia and Luna are excited... now that can fight without accidentally killing literally everyone around them. 

79. Slice of life. Celestia's pranks, and sometimes Luna's when she's awake as well.

82. Celestia gets turned into a Phoenix. She has to find Fluttershy. She enjoys some quality time with Philomena on the way, who she now can understand... somehow. we're here... she's not home..... where... Having fun? DISCORD! This makes sense now...
Why don’t you two go have some fun, relax, and play some pranks... think of it as a vacation.
Discord I swear if you don’t... snap*
Annnd... he's gone...

87. Celestia and luna had children, didn't you know? They're long gone now And had several grandchildren of their own. They were never royalty because they had them when they were fairly young before they were princesses. Those records are long gone as well. The princesses could be distantly related to anyone in Equestria, and would never know. Until a new and improved version of the bloodline detection spell was invented last week. The princesses are curious. 

97. Celestia is no longer chained to her throne. So when a new threat arrives, it's her time to shine again. Too bad she and luna are still very, very, VERY rusty.

98. Someone has broken into Celestia’s secret vault, where she held all the dangerous objects she couldn't destroy or purify.who could have done this? Only Celestia and S.M.I.L.E. knew of its existence. There is a traitor in the secret organization.

111. The start of an entire Alternate Universe. Celestia and Luna ascended to Godhood. At least that's what (insert names) lead many to believe. In reality, they are imprisoned, and their power is being drained to be used by (insert names) for selfish gains. One day someone VERY faithfully in the clergy finds out. They are also the most powerful paladin of the era. It's time to bring divine retribution to the real heretics. 
Or make it only Celestia that is trapped as luna was just banished.

114. Celestia isn't ready to go....she has to be here for the return of her sister... curse you fate... first, you take my sister, now this... no... not yet... I have to save her...  I'm not ready to DIE! no one can find out about... Necrolestia... at least not until the time is right... if it ever is...
Celestia is a revenant, ghoul necromancer, and she needs flesh... I MEAN... followers.....

126. Sombra is back, and he has turned everyone against Celestia with lies and the power of the umbrum, to make you HATE what you once loved!

128. 126 Alternate: Celestia thought everyone turned on her, no one hates Celestia, it turns out that magic/potion was used that made Celestia hallucinate to think everyone she cared about turned on her. A spell/potion that turns love into hate. Chrysalis noticed this when they started 

131. Soldiers from another nation are hunting a fugitive that is looking to take refuge in Equestria. When asked about his crimes, they said it is not of their concern. Celestia disagrees...

170. After banishing her sister, Celestia made a council to rule Equestria in her stead. A thousand years later, the council hasn't been doing good lately. Twilight, daughter of one of the council members, goes against them to find Celestia and figure out why she left.

She convinces Celestia to return and try to resume her rule. but Celestia is very out of practice and a few of the council members are out to ruin her anyway they can... and they do technically have more power and influence than her…

172. Celestia gets ponynapped shortly after her retirement. How? By who? And why? Will anyone even notice? 

175. Celestia has to put her retirement on hold to save Equestria.

176. Celestia has turned evil… or has she? It turns out, not all is as it seems.

179. Celestia looses her sight. Crysalis has some spare eyes around here somewhere that can shapeshift to meet her needs.