I've had this issue for weeks now, so much so that a lot of apps I have are simply not there since I restart the phone to try and fix it and they delete themselves and I have forgotten what they were, or they are listed as NULL in settings > storage and I have no idea what they used to be.
However I just tried this fix I read on another post and I can't believe it worked, but it did.
Click on each app icon (not from settings) that is stuck and it will change to waiting, and a few seconds later update. If the app is missing from the home screen (icon views) and is NULL in the Settings > general > storage then there is no way to fix it, you must delete (via storage page) and re-install from the app store
I do think that it might also be related to free memory, so be sure you also have about 1gb free. I suspect the apps freeze since they are trying to install and then realize there is not enough memory to complete the install and hence get stuck.
One other observation, Spotify went bad on me today and is listed at 699mb, I know its Spotify because I checked yesterday and it was listed at 699mb and I couldn't figure out why. After deleting and reinstalling Spotify (73.2mb per app store description) its now listed at 78mb (reasonable size) on my phone... 699mb down to 78mb?! Something very weird is going on Apple! 😕
Apple you really need to fix this, or at least inform users whats happening and how to prevent it.