Since January 2016, I've been focused on building an expanded set of simple effects that are multi-purpose and light-weight, that can be layered with any other effects, not just those of the same "sets", and used creatively. The result has been the ability to, for lack of a better phrase: Photoshop video.
Whatever you're "whim" is: you should have the tools to be able to make it happen without leaving Final Cut Pro.
Consider adding SC KeyFX, Highlighter 2, Grid (everyone should have a grid to use), Progress Plus, and many more, to your video editing toolbox.
[Edit: I've bundled all the best effects in Sight-Creations Essentials, available here:
https://fcpxtemplates.com/product/sig... ]
... before time runs out (which is very likely to be soon, I'm sorry to say.) Please help out by spreading the word: Twitter, Facebook, Instagram, Pinterest, etc. and links on your own websites would be helpful as well.
Thank you.