"What is an Altar?"
An altar is any structure upon which offerings such as sacrifices are made for religious/spiritual purposes.
List of magick items/tools
Since you don't go into specifics about what magical items you seek to learn about, I'm going to assume you're talking about magical tools. Here's my list:
This is only the basic information about these magick tools, please research on your own for more information. Hope I could help, bless be.