Deathrite Shaman: It doesn't really do anything for your deck. Rather than try to remove the lands and sorceries from your graveyard, you should play less of them altogether.
Codex Shredder: Bad all around. I'd rather see another decent creature in this slot like Llanowar Elves or Young Wolf (which you can sacrifice twice)
Bone Splinters: No no no. Most of the time, you'll get more value out of straight up removal.
Skylasher: It's a blue hoser some of the time and a 2/2 for 2 most of the time. There are a lot of better creatures you can probably put in this slot.
Blood Artist: Should be 4. Artists are amazing and the more the better.
Corpestraders: Really slow card, and you're going to wind up sacrificing it eventually anyway.
Savra: I assume this is kitchen table magic?
Vraska: Vraska doesn't really fit in here. She's cool but there are better planeswalkers for a creature based strategy. For example, Garruk Relentless is only 4 mana, and it creates Wolves for you to attack with/sacrifice, and costs the same as Vraska.
Deadbridge Chant: Cards like Deadbridge Chant are awkward to play with because it takes a long time to set them up and they don't win you the game immediately. So the key point is to get to 6 mana as soon as possible or stall for as long as possible and your deck isn't really built for either of that. Also, every non-creature card in your deck makes Deadbridge weaker.
Take a look at this deck (scroll down to Sepulchral Strength). The key to a good creature sacrifice deck is quantity and value. Stuff like Viridian Emissary gets you a land when you sacrifice it, helping you ramp up. Creakwood Liege generates an army of 3/3s AND pumps up all your other guys, only for 4 mana. Golgari Germination gives you free 1/1s when you sacrifice your non-token guys, which you can sacrifice again, nearly doubling your sacrifices. Your sacrifice outlets (that is, the cards that enable you to sacrifice on demand) are very expensive. Ideally, a sacrifice outlet should be totally free so you have flexibility during combat and blocking.
Here are the parts of a creature sacrifice deck:
Creatures: Lots of them. Ones with on death effects are especially good. If you have some sort of recursion, then Enter-the-battlefield effects also really good. Generally, you want cards whose value is split between their P/T and their abilities, because you're going to be killing them off. Cards that replace themselves, either by getting you more cards or leaving behind a creature (or even coming back as in the case with Undying or Persist) are especially good here.
Sacrifice Outlet: This is a creature or enchantment that you use to sacrifice anything you have out. It should be free, instant speed, with a moderately strong effect.
Sacrifice Value: Blood Artist is hands down the best for this.
Finisher: A lot of cards work off of your graveyard and those should be your game enders. Deadbridge Chant is okay, but pretty slow. Something like Sewer Nemesis or Mortivore are better. They're cheaper, they grow as you sacrifice, and they can be sacrificed themselves in a pinch.
Some cards you should consider for this deck:
Garruk Relentless (in place of Vraska)
Viridian Emissary
Creakwood Liege
Solemn Simulacrum
Golgari Grave-Troll (actually you can just build her a dredge deck)
Sakira-tribe Elder
Oh it has to be Standard legal. Welp, ignore.
