Legendaries with unbalanced difficulties
Fractals sometimes gives core, rarely lode. Upgrade them/ farm fractals. I got way more lodes doing fractals than wasting my time farming like a bot the same add with uberlow chance. Not to forget mystic clover attempts.
Go to Temple of Lyssa when it’s contested, go to the Golem event, dont actually help the Golems or charge up the device, just farm the sparks.
if Lyssa is taken over, move over and capture Dwayna temple and then sparks will spawn around it.
these are your spark farm spots, the other spots are generally a pain to deal with.
another options is the Ascalon Fragment, im not sure if it’s just my group experience with this but i’ve noticed that almost always the Charged Cores/Lodestones come from the Ascalon Fragment.
to a lesser extent i always notice Molten come from the Underwater one.