There is a template which is using an SQL statement to get list of Databases and generate a JSON (http://zabbix.org/wiki/Docs/howto/Microsoft_SQL_Server_monitoring_with_unixODBC_and_LLD). Starting from Zabbix 3.2.2 there is no answer size limitation for ODBC requests accordingly to ZBX-8489. At the same time, Zabbix 3.2.6 truncates the query's result and returns only 2034 bytes.