Christian:

You ask a lot of vague questions:
"if you know the name of a buffer, what is it?"
"can a buffer drive a LED?"

You MUST look in the datasheets, there is no such thing as "a buffer" or "a LED".

In CMOS (74HC) something capable of driving 10mA would qualify for a buffer. In advanced schottkey (74AS) it is probably more like 200mA.

There are LEDs that light up with 1 mA and others that need hundereds of milliamperes.

In light of the above, do you REALLY thank anyone can answer "can a buffer drive a LED?"

Now here is an amazing fact. If you had checked the datasheet for the devices (buffer and LED) you would have known.

Erik