Tendrils of Agony is a popular card to find at the end of Legacy combo decks, The Tendrils combo can sometimes go off as early as your first turn with the right hand
Unlike the list of rarest Pokemon cards I shared, there is more stability to what everyone refers to as the most valuable when it comes to MTG (with some exceptions, which Ill detail below)
I wrote some good rules for driving down the streets of Kaladesh in "Kaladesh Drivers Ed.") Interested in more tips
Even if you dont stick a permanent debuff, Toxic Deluge and similar wraths spike in value
Used as a blunt instrument it can be Nevinyrral's Disk and wipe out the whole board, and if you can show your hand via a small investment you can do it at any time with confidence that nothing on board is likely to be too expensive to take out
In addition, there isnt a clear shell of support for the card right now and thats why I have it all the way down at sixth right now, but the card is still good enough to create archetypes and slide into various midrange decks