Columns Contains all Column objects of a table, index, or key.
Groups Contains all stored Group objects of a catalog or user.
Indexes Contains all Index objects of a table.
Keys Contains all Key objects of a table.
Procedures Contains all Procedure objects of a catalog.
Tables Contains all Table objects of a catalog.
Users Contains all stored User objects of a catalog or group.
Views Contains all View objects of a catalog.
if you are using sql server, you can try
select name from sysobjects where type = 'U'
or
select TABLE_NAME from INFORMATION_SCHEMA.TABLES where table_type = 'BASE TABLE'