for fjordur: use a desmodus and sneak into the fire wyvern trench at night. at the end of the trench is an amethyst cave; keep going all the way back until you hit a big cave full of magmasaurs. use a spyglass to check out the eggs. land next to one, grab it, hop back on, and get out FAST. other hazards besides the magmasaurs include rock elementals, onyc, scorpions, and centipedes.