Anti synergy cards idea for EDHrec

We all use EDH Rec for brewing decks, but when it comes to cards that are synergistic against commanders, you have to do other kinds of digging. For example, my brother has a gruul [[Chishiro, Shattered Blade]] enchantress/artifact slinger +1/1 counter deck while my dad runs a knight tribal [[Sidar Jabari of Zhalfir]]. Against Sidar, the best card in the deck for Chishiro is [[Scavenging Ooze]] but it’s nowhere listed on EDHrec. Wouldn’t it be nice to see cards that are hard counters to commanders? And I’m not talking staples like [[cyclonic rift]].

Main point: There are cards that are generally “okay” for commanders, but because of your opponent they can be some of your strongest cards. EDH Rec should implement a feature for this. I want to see the top cards to use against commander ______.