Zombies is another one of Magic's oldest creature types, even if some of its oldest members had to be backdoored in via errata. Alpha had Scathe Zombies as an actual, er, "Zombies" at the time, so even without errata, technically, they've been with us since the beginning. While Zombies don't have the greatest competitive history compared to humans or elves, they have had their moments, as you'll see below.

Graveborn Muse?

Although I'm still on the fence about whether to include premodern in these articles, Graveborn Muse has seen play in plenty of formats over the years. The fact that it's a staple of the fledgling format is testament to the fact that it used to be good in more well-established formats once upon a time.

Stillmoon Cavalier

If you don't play a lot of Vintage, you might be surprised to see this card here. I was. Now, granted, it mostly shows up in the sideboard, but it shows up there a lot. It has an excellent tournament pedigree in other formats, too, including pro tour Top 8s in both Standard and Extended.

Geralf's Messenger

Kindred decks are only rarely good in competitive formats. Often that's because they are weak to sweepers and removal. Zombies have almost never been a strong Constructed archetype... except Geralf's Messenger made the brainsuckers into a real deck back in 2012. Having your aggressive 3-drop come back and drain an opponent after they tried to kill it made a huge difference. That, and a critical mass of zombies from Innistrad block pushed deck to a GP win and several top-8s.

Tidehollow Sculler

That's 2010 World champion Tidehollow Sculler to you, actually. Admittedly, the "artifact" part of the typeline is more important than the "zombie" here, but it still counts. Sculler was everywhere during its time in Standard and Extended and it still sees modern play in flicker decks today.

Carnophage

Back when creatures were awful, Carnophage was a little less awful. Aggressive decks were not for the faint of heart when Carnophage was around, but this was part of one of the best decks of the era. Suicide Black either killed you fast or died trying, and a turn one 'Phage was one of the best ways of taking the first option.

Gurmag Angler

For quite a while, this basically-vanilla 5/5 was among the best creatures in modern. It even put up performances in Legacy and, to a lesser extent, Vintage. That's a heck of a pedigree for a common with no abilities.

Dreadhorde Arcanist

All right, this looks more like a card you'd expect to see in powerful Eternal formats. Flashing back Ancesstral Recall and Demonic Tutor? Don't mind if I do. This card shows up wherever there are powerful, cheap spells.

Silversmote Ghoul / Prized Amalgam

This gruesome twosome have been doing unfair things since they were printed. Degenerate dredge players love putting them into play for free in any format they can get their hands on, from Arena-only Timeless to millionaires-only Vintage.

Wight of the Reliquary

Another Vintage all-star. This unassuming 2/2 is what makes the Cradle Control deck sing, growing itself and its friend Fiend Artisan while searching up a Gaea's Cradle or a handy Bojuka Bog. It briefly showed up in Modern, too, but it really needs the toolbox lands available to it in the bigger formats.

Gray Merchant of Asphodel

While Gary has never made a dent on bigger formats, he has impacted Standard both times it appeared. It was huge the first time around, being part of the best deck in the format for almost its entire run, circa 2014. Mono-Black Devotion was the entire Top-8 of more than one prestige tournament. It won so many Grand Prix and SCG events and the only reason it never won a Pro Tour is because it was only legal at one, and the card had only been legal for a few weeks.