So I have noticed that the Emerald and Y entries for magneton state that he is capable of raising temperature by 3.6 fahrenheit in a radius of 3300 feet.
So we can get a amount of energy needed to do this.
First convert 3.6 fahrenheit increase to celsius increase, which gives us 2 degrees celsius
Radius = 3300 feet = 1005.84 meters.
Now we will consider than it increases the temperature in a hemeispherical range of radius 1005.84 meters.
Volume of this range = (2/3)(pi)(r^3) = (2/3)(pi)(1005.84m)^3 = 2,131,303,614 m^3
Density of air at 300k (near room temperature) = 1.177 kg/m^3
Mass of this air = volume x density = 2,508,544,353 kg
Specific heat capacity of air (with constant volume) at 300K = 0.7178 KJ/kgK [in this case, volume will be constant)
Energy needed to heat up air = mass of air*specific heat capacity*change in temperature
Energy = (2,508,544,353kg)*((717.8J/kgK)*(2K) = 3.601266 * 10^12 J (approx)
The energy translates to about 860.7232 tons of TNT. Which is Multi-City Block+
Also I think this should scale to pikachu (at least to ash's pikachu) as well.
So the result is MCB+ pikachu and magneton.