No tribal deck has elicited a more passionate response from players, both positive and negative.
I've been a fan of slivers since I decided to collect the entire Tempest block back in the late 1990s. Since then, I've always loved their crazy synergies. I was so stoked when they released the Premium Deck Series' Sliver deck. Back then, I think I paid $19.99 for it at a local Walmart. Alas, over the years, between moving and taking a hiatus from MTG, the deck was lost.
Since I had been out of the game for a few years, Commander/EDH was foreign to me. You mean I can only play 1 of each card other than Basic Lands? Whoa, talk about a bit of a shock! However, once I started thinking about it, I set out to make a fun (and killer) Commander deck that would take advantage of many different slivers' abilities.
To start, I picked Sliver Overlord (as just about everyone else does) as my Commander. The ability to tutor out whichever Sliver you might need based on any given board-state is invaluable. I generally will tutor out Gemhide/Manaweft Slivers first, and then Sliver Hivelord second. I've yet to lose a game once Sliver Hivelord hits the battlefield.
You'll see some stuff in the decklist below that may seem out of place; like Planeswalkers, or original dual lands. I threw these in simply for fun and in the case of the Planeswalkers, added threats.
Coat of Arms is definitely a great card...if your opponents don't happen to be playing tribal decks as well. If you suspect (or know) that your opponents are playing tribal, it's probably better to replace this with Metallic Mimic before the game.
Other creature buffs come by way of Obelisk of Urd and Sliver Legion:
Obelisk of Urd buffs your creatures by giving them a static +2/+2.
Sliver Legion acts as a one-sided Coat of Arms (given that your opponent isn't playing Slivers).
Because of the potential for Coat of Arms and Sliver Legion to help your opponents, you might want to just stick with Metallic Mimic and Obelisk of Urd.
Playing a 5-color deck is no easy feat. These cards are essential in making sure you'll have the mana sources you need to take over the game.
Path of Ancestry
Prismatic Omen, Gemhide Sliver, Manaweft Sliver, and Path of Ancestry are the key cornerstones of your mana generation.
In addition to these mana-fixing options, the deck also runs many tri-color lands.
Are you running a Tribal Slivers Commander Deck? Let us know in the comments below what's been working for you!