Akroma's Memorial is one. Obviously it never sees cEDH these days, but you'd be surprised how many people think every creature-heavy and/or token deck wants it.
But back when Commander had a newbie boom with the first Commander decks, everyone thought it was an auto-include.
The main problem with memorial is that it's probably the most emblematic "win-more" card. I won't call it a staple.
Timmies will be tempted to put it into their decks and when they win with memorial ut, they scream "you see? it works!", without caring if they had already the best table position way before casting the memorial, or if the last 5 games the memorial ended up not useful enough for 7.
I have many players using memorial randomly in my LSG. the best fan are using it in pentacolor tribal dragons and boros aggro.
I think my only decks with Memorial both 1) are capable of producing silly amounts of mana, so the cost isn't too high to play it, and 2) want mass haste for one reason or another. None of those decks are red (or I'd play something like Fervor instead), and the one that's green also has Concordant Crossroads.
and I've PROVEN to some of these players that they aren't necessary to their game: reliquary tower: i've pointed out that card, and then for the subsequent multiple games thereafter, made it a point every single time they got colour-screwed, and every time they've hit their hand limit (they never do!). most players I've done this to STILL keep it in, because "well, you never know if someone casts a prosperity for 20" or ::insert other ridiculous niche scenario here::
Just yesterday I was playing against someone with a Windgrace deck that tutored up Reliquary Tower to avoid discarding a single card. I commented about how a lot of people over-value it, and he just kinda shrugged it off. When you've got 40+ cards hand (which the Windgrace player did achieve the prior game) and have to discard to hand size, you get to pick the best 7 of those 40. Unless you've got Omniscience or infinite mana, you're not going to be casting all those cards. (Of course, that previous game I was controlling his turn with Emrakul when get got the 40+ card hand, so I chose what 7 to keep and chose the 7 worst, but he would have gotten that same grip on his turn if I handn't Emrakul'd him.) Later in the game where he tutored for Reliquary Tower, he had Gitrog Monster and would have benefited from discarding to hand size, effectively getting free looting, and his deck has least 5 cards that can recur lands, three of which recur all of them at once, so pitching a hand full of lands is beneficial to him. But no, Reliquary Tower is too important.
In my Treva deck, I very specifically chose to exclude Reliquary Tower, despite having a fairly large amount of card draw in the list, and I've had people call me crazy for it. But it makes it easier to shuffle my graveyard by discarding Ulamog/Kozilek, and it makes drawing cards with Magus of the Library easier, digging further for answers to things (especially with Alhammarret's Archive and Tomorrow, Azami's Familiar in play; tap one creature to dig 6 deep is awesome).
sol ring: insert a list of decks that have a lot of 1 cards or even worse try to push their general out asap to swing-win (kaalia of the vast, zur the enchanter comes to mind), or whatever synergy with the general. In my 5c child of alara deck, i don't run sol ring because it doesn't do anything for me. child blows up artefacts. when I'm ahead, it doesn't push me to win. when I'm behind, it doesn't help me catch up (by altering the board state), when I'm at parity, there are more effective things i can do to push me to win. Some people have the idea that sol ring is a 100% must include for every single deck that they have, but its not always the case.
I don't have Sol Ring in Child of Alara, because it doesn't help me cast my commander and the deck's goal is to trigger Child every turn.
I don't have Sol Ring in Gaddock Teeg, it doesn't help me cast my commander, my commander prevents me from casting many of the things it would help most with (so I don't run them), and it's a hate-everything deck with cards like Null Rod, Stony Silence, and Kataki, so Sol Ring is more of a liability than an asset.
I don't have Sol Ring in Atraxa, because it doesn't help me cast my commander, and it's a curses/enchantress build with little use for artifacts, so instead of running Sol Ring I run mass artifact hate.
I don't have Sol Ring in Goreclaw, because many of my spells cost no generic mana thanks to my commander, and it's green stompy with little use for artifacts, so instead of running Sol Ring I run mass artifact hate. (Titania's Song is a hilarious card, btw.)
Two Score, Minus Two or: A Stargate Tail
(Image by totallynotabrony)
Two Score, Minus Two or: A Stargate Tail
(Image by totallynotabrony)
In my Treva deck, I very specifically chose to exclude Reliquary Tower, despite having a fairly large amount of card draw in the list, and I've had people call me crazy for it. But it makes it easier to shuffle my graveyard by discarding Ulamog/Kozilek, and it makes drawing cards with Magus of the Library easier, digging further for answers to things (especially with Alhammarret's Archive and Tomorrow, Azami's Familiar in play; tap one creature to dig 6 deep is awesome).
I don't have Sol Ring in Child of Alara, because it doesn't help me cast my commander and the deck's goal is to trigger Child every turn.
I don't have Sol Ring in Gaddock Teeg, it doesn't help me cast my commander, my commander prevents me from casting many of the things it would help most with (so I don't run them), and it's a hate-everything deck with cards like Null Rod, Stony Silence, and Kataki, so Sol Ring is more of a liability than an asset.
I don't have Sol Ring in Atraxa, because it doesn't help me cast my commander, and it's a curses/enchantress build with little use for artifacts, so instead of running Sol Ring I run mass artifact hate.
I don't have Sol Ring in Goreclaw, because many of my spells cost no generic mana thanks to my commander, and it's green stompy with little use for artifacts, so instead of running Sol Ring I run mass artifact hate. (Titania's Song is a hilarious card, btw.)
Two Score, Minus Two or: A Stargate Tail
(Image by totallynotabrony)