Query below lists user schemas in SQL Server database, excluding default db_* , sys, information_schema and guest schemas.
If you want to list all schemas use this script.
Query
select s.name as schema_name, 
    s.schema_id,
    u.name as schema_owner
from sys.schemas s
    inner join sys.sysusers u
        on u.uid = s.principal_id
where u.issqluser = 1
    and u.name not in ('sys', 'guest', 'INFORMATION_SCHEMA')
Columns
- schema_name - schema name
- schema_id - schema id, unique within the database
- schema_owner - principal that owns this schema
Rows
- One row represents one schema in a database
- Scope of rows: all schemas in a database, excluding default db_* , sys, information_schema and guest schemas
- Ordered by schema name
Sample results

 
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                 
                                                             
                                                             
                                                             
                                                             
                                                                 
                                                             
                                                             
                                                                 
                                                             
                                                             
                                                             
                                                             Piotr Kononow
                                                                        Piotr Kononow
                                 SQL Server
                                                                SQL Server
                                 Azure SQL Database
                                                                                                Azure SQL Database
                                             Snowflake
                                                                                                Snowflake
                                             Amazon Redshift
                                                                                                Amazon Redshift
                                             IBM Db2
                                                                                                IBM Db2
                                             Vertica
                                                                                                Vertica
                                             PostgreSQL
                                                                                                PostgreSQL
                                             MySQL
                                                                                                MySQL
                                             MariaDB
                                                                                                MariaDB