Without breaking your fast?
I only use Himalayan salt, either straight or a pinch in my water (helps with brain fog & tiredness) potassium pills 5-10 tabs a day (a must for relaxing effects while extended fasting) & magnesium glycinate (great before bed for relaxation as well). I’l haven’t tried making a mix of my own yet but there are plenty of recipes out there too. Other premade electrolyte mixes tend to have sweeteners that break fasts so I get too hungry using them outside of the eating window.