For some reason, I'm missing a bunch of icons in KDE. I am using Numix Ultra Flat Icons and that should have icons for almost everything but most of the basic icons are missing (folders, txt files etc). The icons will show up super tiny if I hover over them in Dolphin. I have attached some screenshots below.

Images: https://imgur.com/a/6uTT9

What OS do you use? You might want to try installing breeze-icons package, it might solve your problem. When Numix Ultra Flat Icon will be not found, it should fallback to default Breeze icon

Yeah, it looks like many icons were missing from the iconpack that I was using and for some reason, it wasn't falling back to breeze icons. I fixed this by using a different icon pack. Thanks for the help!