I am just curious, there are many workshop out that are "sponsored" by some unknown engine oil brand. And most of them will going to use that brand of engine oil if you do no have a desire brand when bringing your car to service there.

Actually what are they? are those small unknown brand fake oil or low quality brand tiputipu? Or are are something like made by big company but rebranding into other unknown named brand? Is it recommended to use?

some example of unknown brand
Voils, G Energy. Eximius, Arrow, Kings etc