These are the basic alloys that are sold. Sheet and plate come in
3003, 5005, 5052, 5086 and 6061. 3003 and 5005 are used for general fabrication. 5005 is a little stiffer, where as the 3003 are very soft and easy to work with.
Extrusions come in 6063, 6061, 5086

3003
The simplest alloy is 3003 which contains about 1.2% of manganese in addition to normal impurities. This alloy contains about 98 % pure aluminum. Other alloys may have 4 or 5 elements added.
3003 and 5005 are used for general fabrication. 5005 is a little stiffer, where as the 3003 are very soft and easy to work with.

6063 T5
This alloy is available in extrusions only,
6063 is used primarily in general construction and has softer strength qualities should you require it.

5052 H32
This alloy available only in sheet.

6061 T6
This alloy is available in sheet and extrusions and
6061 is used in applications where enhanced rigidity and stiffness is required.

5086
This alloy is available in sheet and extrusions.

This alloy is used primarily used for marine ship building repair and construction and possess a high tolerance to electrolytes.