Since these cards are often faked, it's safest to buy a graded copy anyway, which is much easier to appraise than a raw copy
You'll also wanna learn how to spot the different rarities, such as Common, Rare, Super Rare, Ultra Rare, Secret Rare, Ultimate Rare
for example, if you have drawn multiple copies of Kolvori and want to get use out of the extra copy, or if you have nothing to do on Turn 2 and developing a slightly-below-rate mana rock is better than doing nothing
Banish any monster destroyed by battle with a "Dinomist" monster you control
Also, since you are casting Gravecrawler rather than reanimating it through some other effect, many of the traditional activated abilities or cast spells used to check graveyard players fail to nab the 'Crawler since generally you'll have priority before casting, and by the time they have a chance to react, it is already on the stack and not in the yard
a playset of this is actually eight Fogs