Is your Galaxy S4 rooted but stock? Do you want custom ROM like mods? Then you have to check out NottachXposed!
This app was made for the AT&T version but it does work on the Verizon version as well! I've had this installed for a couple weeks now and absolutely love all the tweaks it offers!
All you have to do is install 2 .apks. (no flashing required!)
Check out the original thread for download links and insturctions here. Make sure you download the latest version.