You can read the full page for these different types of visas by click on one of the pages on the right.
Major areas of concentration are the following:

H-1B (Professionals); H-1B1 (Professionals from Chile and Singapore);
L-1 (Managers, Executives and Specialized Knowledge Workers) ;
E (Investors and Traders) ;
R (Religious Workers) ;
P (Artists and Entertainers) ;
Labor Certifications;
National Interest Waivers;
Aliens of Extraordinary Ability;
Health Care Workers;
Student Visas;
TN Visas;
Business;
Federal Court;
Greencards and citizenship;
Professors and Researchers;
Adoptions;
Family and Marriage Petitions ;
Asylum, Deportation and Cancellation of Removal.