The following are some ways to begin collecting tools:

Tools of a specific company or maker - for example, L. Bailey Victor tools, Seneca Falls

Tool Company tools, Miller's Falls tools, Disston Saws, Chelor planes, etc.

Tools of a specific type - hammers, braces, axes, saws, patented planes, transitional planes, treadle-powered machines, etc.

Tools of a specific period - tools from 1850-1900, post WWII era tools, etc.

Tools from a specific place - Scottish tools, tools from Massachusetts makers, etc.

Tools of a specific occupation - cooper's tools, machinist tools, watchmaker's tools, garden tools.

A combination of one or more of the above categories -- for example, one each of a specific type of Stanley tool, i.e. all Stanley saws, all Stanley marking gauges, all Stanley planes, etc.

A "type study" of one specific model, for example, a type study of Stanley #6 jointer planes or Norris A5 smooth planes.

Tools that show how a specific idea progressed over time, for example tools tracing the development of the plane's adjusting mechanisms, or tools showing how an early patent was bought out and developed by another company.

-Wikipedia