Artifacts are very useful when played skillfully and game-slowing duds when played the way a beginner like me often plays them. The
Mirrodin and
Scars of Mirrodin blocks and the first sets of each block by the same name are loaded with artifacts. It is even possible to build an artifacts-only deck-60 for Standard with 15 in the sideboard, and 100 for Commander. Artifacts, like enchantments, come into play and affect play of all cards you have. Here are a few examples.