What's left available to the US is the remaining pressure that China can place on DPRK. From earlier today:
“Just spoke to President XI JINPING of China concerning the latest provocative actions of North Korea,” Trump tweeted. “Additional major sanctions will be imposed on North Korea today..." source
China has ramped up sanctions as well the last few months, but it has stopped short of cutting off its energy supply to the country or completely banning North Korean exports. Outside of some shady alleged energy trading with Russia, North Korea is almost completely dependent on China for energy. China has been unwilling to crack down on North Korea to the extent the US would like because if the DPRK becomes a failed state then China will have not only a dangerous and unpredictable situation at their doorstep but also a massive refugee crisis on their hands.
The US is hoping that the North Korean launching of an ICBM is enough to persuade China to play one of their trump cards (no pun intended).