If you aren't sure of a plot then use these to help you out. They apply to every series unless I say otherwise.

1. What life was like during the War for Cybertron.

2. One character from another series visits (Crossover story)

3. Character X OC

4. Pregnant female OC or bot. (The no smut rule still applies)

5. A huge battle between the Autobots and the Decepticons which results in the Bots losing (or Cons, depending on the P.O.V) loosing.

6. Meeting their first Decepticon. (RB/RBA)

7. A human learns their secret.

8. An injured Mini-con is found and the team must take care of them.

9. An Autobot crash lands on Earth and is found by Decepticons, or a Decepticon crash lands on Earth and is found by Autobots.

10. There is a huge threat which leaves the team needing help from others. (This could potentially be a crossover plot)

11. A Transformers AU meaning they are humans.

If there is anything you want me to add then let me know!