There seems to be nothing better that a completeness. Google has recently published a Noto font that contains more than 800 languages and 110,000 characters. All Noto fonts are licensed under OFL. There will be no ‘tofu’ anymore! Enjoy!
But we’ll see if it contains this ‘Biang‘ Chinese character or not later. But since it’s not in unicode yet, likelihood it will miss. D’oh!