I just realized that you can Control-C/Control-V to copy and paste entire blocks in Builder from one screen to another. Everything is duplicated, including layout, data source and display rules.
I am duplicating a complicated screen with a couple minor changes to test something out before breaking something that's already working, so this trick saved me a ton of time. Hopefully, it will help someone else out, too.
@Isaiah this is great, thanks for sharing the tip with the community! Also wanted to mention that you've inspired the team to write an actual article on this concept as well; so kudos to you. 
We really appreciate the feedback and I'll post back here once the article is created.
Will also note, you can go one step further with the ctl-c/ctl-v by copying and pasting the whole screen as well, instead of just at the block level. I do this quite often for the very same reason you described - it's perfect for testing and experimenting. Check it out in action...
Anyway... Yes if you come across any more useful tips & tricks, please keep passing them along here. We all benefit.
And here's the article! 
Yup, there's a lot of Crtrl+C/Ctrl+V functionality that's not obvious but very useful.
