WD40 for aluminium and some brasses, it’s expensive in aerosol form so I buy mine by the gallon then dispense using one of SWMBO’s old hair dye bottles with a syringe attached to the tip with heat shrink tubing, dont waste much and get it right on the spot.
Machine mart sulphur based cutting fluid for all ferrous (except CI) again bought by the gallon and dispensed in the same fashion as the WD40.
Soluble cutting oil I buy from “The Baltic Oil Works” locally for about £20, a gallon lasts me for about 12 months used mainly in my old Qualters & Smith donkey saw.
Regards
Paul