Some icons appear to be heavily inspired by LV.
Here are three icons (circled) from Flat-UI: http://i.imgur.com/xDDULcG.png
You can see that the gears and news icons do bear some similarity to LV's versions: http://dribbble.com/shots/800428-LayerVault-icon-set-for-del... and http://imgur.com/rli5IVU (the latter via http://news.ycombinator.com/item?id=5332741)
In addition, LV claims that Flat-UI ripped off a number of other icons from dribble.com, such as this clock and map (Flat-UI above, originals below): http://cl.ly/image/3Q181w0b1u2K (original dribble links: http://dribbble.com/shots/695458-Nasa-Playbook-Icons and http://dribbble.com/shots/877061-Map-2013).
Finally, the color schemes have been claimed to be identical: http://pixxel.co/feed/layervault-issues-dmca-takedown
LV appears to be confused as to what constitutes copyright infringement. None of these icons are actually copies of the original, and even if they were LV would not have a right to issue a DMCA takedown for the ones they didn't own.
This seems to be a massive PR blunder for the LV guys. They could have put up a blog post enumerating how many of their (and others') designs were ripped off (which is not the same thing as copyright infringement) and probably garnered some internet sympathy. Now, by misusing the much-hated DMCA takedown notice they've positioned themselves in the same camp with all the DMCA bullies we have grown to loathe.