Phone Storage

Is there an App that can locate large files in phone storage? I've downloaded several from the Play store, but they only seem to specialize in SD storage. My problem is on the phone. I have just over 1GB, but less than 45 available. According to AppMgrIII I only have about 300MB of applications installed on the phone, everything else is on the SD card, so where is the other 700MB. I did try x-plore file manager, but after an hour of scrolling, I searched less then 1/3 of the top level folders and gave up. I'm hoping there is something that will just search the phone storage and report the size of large files / folders.