A Standard Will  deals with uncomplicated situations, and generally will/could include appointment of executors,  guardians, gifts & distribution of the estate.

A Specialist Will  would/could include all the above but may need the inclusion of a specialist trust, (Discretionary Trust, Lifetime Trust, Right to Occupy Trust, Mutual Wills, Wills in anticipation of marriage) or there are special circumstances where the Will drafter has to create a unique clause or clauses to cover a particular need.