KOReader isn't necessary, unless you read PDFs or have really unusual preferences how the text should look.
Extended driver is good to have if you want to read kepubs instead of epubs.
Personally I don't find much use for KoboUtilities, but others do. So that depends.
Most of the mods are now all in one place, Kobopatch. So if you're interested in them, you don't have to read 100 threads all over the forum and download 20 different patches from different threads. The patches and their descriptions are now together in the kobopatch.zip.
https://www.mobileread.com/forums/sh...d.php?t=330070