This set of fetch lands are going to be the most expensive of the bunch, aside from maybe Prismatic Vista (mentioned below)
Not only do they prevent your permanent from being removed, but they also allow you to point that removal elsewhere
That being said, Amethyst already has good access to draw with Friends, Rabbit, Castle, and more
This allows for the perfect intersection of defensive interaction (like Red Elemental Blast and Veil of Summer), brutal stax effects (like Archon of Emeria, Collector Ouphe, and Drannith Magistrate), and a consistent combo thanks to the many different tutors in the list
( To get rid of all of your chase cards quickly, take them to your local games shop and sell them individually
This can lead to plenty of extra mill over the course of a long game, especially in Commander, where this adds each-opponent mill to any instances of single-target mill