Like most Pokmon cards, the value of Excadrill depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Fusion Strike)
The Lord of Pain has the added bonus of making sure your opponents can't gain life, which means there's no escaping their inevitable death
The Zealot even lets you sacrifice artifacts at will
But one of the many cool things about fantasy is that you get to travel to other realms
In summary: If most are your decks are two colors, and you want your players to be able to cast their spells reliably according to Frank Karstens definition you should include no fewer than 60 fixing lands in a 360 card cube (~17% of the cube)
[16] Another early error saw a limited number of cards printed with the back art of a Magic: The Gathering card instead of the normal back art