Magewright's Stone in a vacuum is just an okay card, but when combined with other tap effects it can become incredibly strong
1 Collector Booster, 9 Play Boosters, 2 Traditional Foil Extended-Art cards, 32 Full-Art Land cards (16 foil, 16 nonfoil), 1 Spindown life counter, 1 special foil FINAL FANTASY card storage box, and 2 reference cards
Rather than create another auto-include like Arcane Signet, the idea with three mana value rocks is that they can do something additional to make them a bit more interesting
Online communities like r/BudgetBrews (Reddit) are full of ideas for cheap decks
Track Down will scry 3 and let me reveal the top card of my library and draw it if it's a creature or a land
Suffice to say, if these did come up for sale on the open market they would fetch a tremendous sum