Slivers

[Kaworu, the Fifth Child]

Maybe {Obelisk of Bant}?

[Piotr]

That would swing mana statistics considerably, but I'm not sure if for the better?

[FustyDavorite]

Maybe {Obelisk of Bant}?

...  {Darksteel Ingot}

[Piotr]

Maybe {Obelisk of Bant}?

...  {Darksteel Ingot}

In my Needed, thanks

[Aladormax]

I would suggest  {Manaweft Sliver} in here as well. Mana fixing is awesome and having two  {Gemhide Sliver} in edh is never bad.

[Aladormax]

After I looked over this list, I noticed that you could add  {Descendants' Path}, and  {Aluren} for more awesomeness.

[McAtoms]

 {Door of Destinies} seems like it would be pretty killer here.

[Spencer Addington]

{Coat of arms}?

[Spencer Addington]

If your commander is {sliver queen} you should add {mana echoes}.

[Piotr]

I would normally start with {Sliver Overlord}.