--Get the list of all Login Accounts in a SQL Server
SELECT name AS Login_Name, type_desc AS Account_Type
FROM sys.server_principals 
WHERE TYPE IN ('U', 'S', 'G')
and name not like '%##%'
ORDER BY name, type_desc


--Get the list of all SQL Login Accounts only
SELECT name
FROM sys.server_principals 
WHERE TYPE = 'S'
and name not like '%##%'


--Get the list of all Windows Login Accounts only
SELECT name
FROM sys.server_principals 
WHERE TYPE = 'U'


--Get the list of all Windows Group Login Accounts only
SELECT name
FROM sys.server_principals 
WHERE TYPE = 'G'