The following resources will help you develop your contract document packages including material selection, creating drawings, writing specifications, and developing contracts.
AIA Contract Documents
The American Institute of Architects has developed standard contracts that have been vetted by attorneys from architecture firms, owners, and contractors over many decades. These are commonly used and well known in the industry. You can purchase a license at AIAContracts.org.
Construction Specifications Institute
CSI was founded in 1948 and has been developing systems for managing the extensive information in architectural documents. They develop MasterFormat the most popular standard for writing construction specifications. CSI also maintains Uniformat, a commonly used format for preliminary project descriptions.
UNIFORMAT II or ASTM E1557
UniFormat II is a guide for developing preliminary project descriptions in the early phases of a project. UNIFORMAT II is also known by the standard ASTM E1557, Standard Classification for Building Elements and Related Sitework.
ARCAT calls themselves "your complete source for finding, selecting, detailing and specifying building products." You can search their directory by CSI division or by category. The library includes a large collection of BIM objects and CAD details. They also have specification writing resources including outline specs and a tool called SpecWizard.
Past generations of architects used to open the iconic green Sweets catalogs when they needed to find product manufacturers. Now, Sweets is available online. You will find outline specs, BIM objects, CAD details, and manufacturer catalogs.
4Specs has been building their online building product database since 1996. While not as polished as other online catalogs, 4Specs gets the job done as a simple, no-frills listing of building material manufacturers. Get straight to the manufacturer's website without much fuss.
US National BIM Standard
The National Institute of Building Sciences maintains the National BIM Standard for the United States.
US National CAD Standard
In addition to the National BIM Standard, the National Institute of Building Sciences buildingSMART Alliancemaintains the United States National CAD Standard.