magic set booster box Magic: The Gathering Core 2019 9 commons Magic the Gathering: Lost Caverns

Take this Water-type deck list, for example

Forbidden Cards Forbidden Jowgen the Spiritualist X LIGHT Level 3 [ Spellcaster / Effect ] ATK 200 DEF 1300 You can discard 1 random card from your hand to the GY

First, adding hex proof makes it much less likely that your opponent will punish you with a Field of Ruin after sacrificing two other lands to get this out

He overlaid for Number 11: Big Eye , took control of Cyber Dragon Nova and Xyz Summoned Divine Dragon Knight Felgrand

Their primary use is for submitting cards to grading services like PSA

You shouldn't buy the set today, but it was worthwhile when it first came out