In my refinery system, I have built up on a neighbouring HMC with one biological life form type the following: 1x T1 surface Colony port, 1x T2 High-Tech settlement, 3x T1 Small Agriculture settlements. This gave me a decent and varied output as seen in the screenshot below. I have also filled every free surface slot in the system with similar T1 small agri settlements, giving the resulting economy:
"StationEconomies":[
{ "Name":"$economy_Agri;", "Name_Localised":"Agriculture", "Proportion":2.800000 },
{ "Name":"$economy_Extraction;", "Name_Localised":"Extraction", "Proportion":1.400000 },
{ "Name":"$economy_HighTech;", "Name_Localised":"High Tech", "Proportion":1.300000 },
{ "Name":"$economy_Terraforming;", "Name_Localised":"Terraforming", "Proportion":1.000000 },
{ "Name":"$economy_Refinery;", "Name_Localised":"Refinery", "Proportion":0.200000 },
{ "Name":"$economy_Military;", "Name_Localised":"Military", "Proportion":0.050000 } ],
"DistFromStarLS":45.152748, "LandingPads":{ "Small":4, "Medium":2, "Large":2 } }
Market readout: