First ever magic deck,Totentanz, Swarm Piper commander deck.

[oak sphinx]

https://www.moxfield.com/decks/Txccbs_B4Ee59c5jgjZfpg
My first attempt at making a deck help is welcome. I feel there are few strong rat creatures that could be added but i am unsure where to make cuts. Also i have no clue how my lands should be structured other then i should have 37 of them.

[nimble ferry]

For lands 37 is a good number but having a few non basic lands that can tap for either or both Rakdos colors will be good. If you can avoid lands that enter tapped, try and do so. Some suggestions are [[Dragonskull Summit]] , [[Smoldering Marsh]] , [[Shadowblood Ridge]] , [[Thriving Moor]] , Thriving Bluff]] , [[Sulfurous Springs]] , [[Haunted Ridge]] , and [[Foreboding Ruins]]

Rat Colony is a good one, but usually only because you can have several in your deck. While not a rat, my Totentanz deck makes great use of [[Funeral Longboat]] to turn tokens into current damage and potential future blockers

[lethal sparrow]

https://scryfall.com/card/khm/238/funeral-longboat

Funeral Longboat <:mana2:292901509060886528>

Artifact — Vehicle
Vigilance
Crew 1 (Tap any number of creatures you control with total power 1 or more: This Vehicle becomes an artifact creature until end of turn.)
"Cast onto the windless water, he drifted until the sea turned to sky." —Saga of the Lost King
3/3

[nimble ferry]

[[Phyrexian Altar]] and [[Ashnod's Altar]] also put in a ton of work in a deck like this

[lethal sparrow]

https://scryfall.com/card/2x2/311/phyrexian-altar

Phyrexian Altar <:mana3:292901508771610624>

Artifact
Sacrifice a creature: Add one mana of any color.
"Unskin these impure bodies, Great Yawgmoth, that the flesh may welcome your blessings." —Phyrexian Scriptures

https://scryfall.com/card/cmm/368/ashnods-altar

Ashnod's Altar <:mana3:292901508771610624>

Artifact
Sacrifice a creature: Add .
"If you work at sawing up carcasses, you notice how the joints fit, how the nerves are arrayed, and how the skin peels back." —Ashnod, to Tawnos

[oak sphinx]

thanks for suggestions @nimble ferry am getting into magic and lands are by far the most confusing aspect. If you can send me your list so i can compare it to mine that would be great. After looking at some other decklists wave of rats seems like a card i would add the most for now.

[deep shoal]

If you're looking to see a full list that others have made, moxfield has a great feature that lets you explore other lists and can filter it to a specific commander.

1. Navigate to moxfield.com
2. Select Explore > Decks
3. Select Advanced Search (it's under the search bar on the right side)
4. Find the commander you're interested in in the Commander input and select Search (I also sometimes play around with the sort field to show me the most popular lists depending on what kind of lists I want to look at).

For instance, here's a link to all the Totentanz lists organized by likes: https://www.moxfield.com/decks/public/advanced/likes?sort=likes&board=mainboard&commanderCardId=WaKlZ&commanderCardName=Totentanz%2C+Swarm+Piper

EDHREC has a similar feature (though it's not as clean/easy to view)