Sure. Try creating your own project. What are you interests and hobbies? See if you can create an application which would be useful to you and/or others who have the same interests or hobbies.
I enjoy running, so I am currently building an app that runners can use to create unique Half Marathon and Marathon training programs customized to each runner based information entered into the app.
The other option is to take the existing FCC projects you have already created and expand on them.
I was thinking more on ways to practice specific aspects/lessons that are taught. If I start a project (which I plan to do a couple once I finish this curriculum), I’ll get a lot of practice, but there will inevitably be things I don’t practice since they don’t relate to it. I’d like to practice each specific lesson a lot, to make sure I don’t miss committing anything to memory for later.
You don’t need to remember everything
Why instead when you need to know how something works you go to search about it?
Do not worry or concentrate too much on memorization. As far as I know, even senior developers have to google how to do x in y language. It is part of the job to be able to google and that is why websites like stackoverflow exist, because you don’t have to memorize, as long as you understand the concepts, memorizing syntax and other trivialities comes overtime. It would be amazing to remember everything we read, I have taken all possible courses on those subjects, done assignments to drill into my head but I continue to look up basic things. I would say just build things.