Slivers are a very powerful creature type in the Magic the Gathering card game. Almost every sliver in the game has an ability that helps other slivers, whether it is giving them haste, pumping their power or toughness, giving them flying, or almost any other ability you can thing of. Having a lot of slivers on the field can make a huge game changing difference.
Every color in Magic the gathering has had slivers as a creature type. That is one of the things that slivers do, is spread throughout all colors of magic in order to bring all of the abilities collected in magic the gathering to one creature type. There are even some artifact slivers from older sets that are very useful since they do not require a color and can be played no matter what lands you are drawing.
The best part about slivers is there ability to come out onto the board quickly. This is thanks to the newer sets additions to the creature type that give all slivers haste, and the ability to tap for mana. This means you can bring out a creature and tap it for mana in order to bring out a second one.
There is one major difference between older slivers and the ones in modern sets. Older slivers are written so that their abilities go to all slivers in play, which does not seem like a big deal, but is devastating to yourself if you are playing an opponent who is also using slivers. The more modern slivers have come out with the words you control put on them meaning that only the slivers that you control will be given the abilities that are given by a certain sliver.
If you are going to build a sliver deck it is advisable to limit yourself to only two or three colors and to make one of those colors green. Green has slivers that give all other slivers and themselves the ability to tap for any color mana you choose which will fix potential mana problems, and also make the deck come out much faster.
The second one you may want to choose is red, red gives your slivers haste, provoke, first strike, and other abilities and power and toughness boosts.
When constructing a sliver deck, it may be helpful for you to also look into creature types known as shape shifters. These creatures are or can become any creature type you choose and can help you do things that other slivers can not. This is especially true for older artifact creatures, since you will want them to help you play spells when you do not have the right color mana for the cards in your hand.
One thing you should be wary about slivers is damage. If you lose a creature that pumps your other creatures, all of your creatures toughness will go down, which means they may have survived an initial fight with an opponents creature but once their toughness goes down they will also die since the damage was already dealt to them.