Master

 The main part of the Sybase instance

 Model

 Template for creating new databases

 Sybsystemprocs

 System supplied stored procedures

 sybsystempdb

 Distributed transaction management    

 tempdb

Group by, Order by, etc Sorting operations

 sybsyntax (optional)

 Syntax , help on sql statements

 dbccdb (optional)

Consistency checking

 sybsecurity (optional)

If Auditing is required.