Ok, just little ideas that I wanted to share on here. You can change them up a bit, if you want. I'm new to the group, BTW. Here goes:

1) A story about the CMC:

The CMC have been trying to get their cutie marks for a while. After all their attempts, Scootaloo and Sweetie Belle and Babs Seed get theirs. But Apple Bloom still hasn't gotten hers yet. She starts to feel left out of the group.

2) A story about Cadence and Twiliy:

In an alternate world, Cadence and Twilight are sisters. The story takes place when they are fillies. Cadence gets kidnapped one night by someone (maybe Shining Armor) because she's a princess, and Twilight doesn't know what to do. She goes on an adventure to save her big sister.

3) A story about Daring Do and Twily:

Twilight is a big fan of the Daring Do books, almost as much as Rainbow. She was amazed when she found out the author of the books was actually Daring herself. When Twilight bumps into her, she never guessed that she would save her instead of the other way around.

4) A story about Rainbow Dash and Scoots:

Scootaloo is older now and can fly a lot better than when she was little. When Rainbow Dash hurts her wing right before a big race that determines whether she can become a wonderbolt or not, Scootaloo has to step in to race for her. If she wins, Rainbow Dash gets another chance to do the race another day, plus Scoots gets in, as well. If not...well, let's just say Rainbow won't be too happy with her.

Hope you like these ideas! Thanks for reading!