The way i beat cosmic monoliths is making sure magic defense is up to survive the laser, using milk and a softdrink on lance, and using a max level air strike to kill it in one hit.
The easiest topaz to get is the one under the floorboard... There is a mole glyph which would make you think of digging, and arrows pointing right at the floorboard. How could you miss it?
Why would anyone buy trading cards when its exactly the same online? You would have to spend a ton of money to get enough of the right pillars/pendulums too.