What battery should I use to wire a 3V LED
Take care - a LED will draw almost no current just below its rated voltage but a very large current just above.  If you don’t use a resistor then you’re relying on the internal resistance of the battery - for a coin cell you might get away with this but for a larger battery the excess current could destroy the LED.  There are a few LEDs available with current-limiting built in, although in general using a resistor is a simple and effective solution.