We mostly know Underground Toys from their Doctor Who merchandise. However they do not manufacture them - the true manufacturers are a UK company called Character Options. Underground Toys just distributes DW merch in the US.
There was not a lot new with Doctor Who at the booth, and absolutely nothing with Capaldi's likeness. They did have the War Doctor 5" on display. I asked a rep about the future of the 5" line and they didn't know for sure, but they said it was likely they would continue with the Doctors only.
The monster from 'Hide"
Mr. Potato Head Doctor Who and Dalek
Weeping Angel Stress Toy
War Doctor's Sonic Screwdriver
3 3/4 figures
Underground toys is also doing Star Wars merchandise