I'm trying to retreive the results from all trapper items, I assume it is stored in the database under the history table but would like to confirm if maybe it's stored somewhere else.
It doesn't depend on Type of item (Zabbix Agent, Zabbix Trapper, ...), but on Type of information (Numeric (float), Character, Text, ...). It will be in some history* (history_uint, history_str, ...) table.
But keep in mind, that direct DB access is not good idea. Better concept is the API access - https://www.zabbix.com/documentation/2.4/manual/api. Just construct API request and then you don't need to care about DB table name.