Whoops, I'm a bit late to the party. Any inexpensive cards that could replace Cavern of Souls and Aether Vial ? Thanks!

querfquake personally, I use Ancient Ziggurat and Descendants' Path

I know this is kinda old, but the new Cloudshredder Sliver May work here. Maybe instead of the 2 Striking Sliver copies

Crystalline sliver in sideboard or one in main needs to be removed. There are 5 total

Your deck is good but remember all slivers they are creatures with aura together like a Paladin using any aura skill in Diablo 2 Lord Of Destruction, one sliver bring an effect to all slivers in game or all of your slivers. So don't need 4 copies of Cloudshredder Sliver to all have Flying and First Strike, intead put a instant or sorcery to Draw card and gain 1 turn advantage! 4 Gemhide Sliver and 4 Manaweft Slivers is necessary because of early mana 5 colors! That old Crystalline Sliver with Shroud ability is not too good as Ward Sliver that can have protection against a selected color. One sliver with Shroud can die in combat easily and a Ward Sliver can survive with protection from black for example. All slivers can not be target by black spells or black source and if you block any black creature your sliver don't die!! So change 4 Crystalline Sliver to 3 Ward Slivers and see the difference!! First strike in magic means victory so you need 3 Striking Slivers or 3 Lancer Slivers or 3 Bonescythe Slivers with Doublestrike!! There is no need of Mutavault, Thran Quarry, Path to Exile, Relic of Progenitus and Swang Song. Instead plays with Instant or Sorcery to draw a card or draw 2 or draw 3 cards to take turn advantage. When you draw one card means you are 1 turn advantage and when you draw 2 cards it's means 2 turns advantage!! The best Sliver combo card is Tribal Unit: all slivers get +5/+5 for example and with 1 Brood Slivers (summon sliver) with 1 Essence Sliver (gain life) with 1 Shifting Sliver (very OP) this way you win easily! I play Sliver deck for 10 years of experience.

Tesseralisk all those cards you mention are very expensive usually this deck wins turn 3 or 4 at most you don't need any of those cards just try the deck and you will see how useless mana slivers or ward sliver is un this deck.

right now you got eight slivers that give all slivers flying, which seems a bit excessive. also Sidewinder's ability also doesn't stack.

also what about Back to Nature?

and what about Return to the Ranks?

Deadpan_Serious uhh, flanking stacks...

oh whoops. i was under the impression keyword abilities can't stack. guess i was mistaken.

you know what's funny, it's a Sliver deck, yet 90% of the money spent on it is spent on lands and accelerators.

I'd recommend switching Gemstone Mine for Unclaimed Territory since it's another cavern of souls and it lasts longer than Gemstone Mines

I ran the heartstone-ashnods alter-sliver queen combo for infinity mana and slivers but it wasn’t easy to pull off

You should replace some lands! Try to play: cavern of souls x4 Sliver hiver x4 Unclaimed territory x4 Secluded courtyard x4 Ancient ziggurat x4 / x2

Come to have a look to my deck! It's quite similar to yours