I have many apps in my iTunes library that I do not use and do not need. I'd like to delete these apps entirely from my iTunes library. I have deleted them from my phone with the wiggle method. I don't want them in my library at all.
iPhone X, iOS 12.0.1
While cannot erase purchases from your purchase history, you can hide them. See Hide apps for your iPhone, iPad, iPod touch, or Mac - Apple Support.
tt2
If by library you mean the Purchased List in the App Store App, they cannot be removed from there. That is a historical purchase list and holds all apps you ever bought or downloaded for fiscal purposes. It cannot be modified, anymore than you can wipe out your purchase history on your credit card from your bank's records, or the store's records.
While cannot erase purchases from your purchase history, you can hide them. See Hide apps for your iPhone, iPad, iPod touch, or Mac - Apple Support.
tt2
How can I delete unwanted apps from iTunes library on my iPhone X?
