A better question to ask would be "what are hydrocarbons not used for?" I can't think of an answer except anything that we don't want to buy - the way I see it, oil is the lowest common denominator of our modern consumerist society (though steel runs a close second - we wouldn't have oil without steel, but nowadays we wouldn't have so much steel without oil).
What about things that are grown naturally - like vegetables? Even then it is used - most of the fertilisers and pesticides that are used in modern farming are made from oil.
What about the stone that can be used to build a house? Stone is quarried using huge machines powered by diesel, lubricated by oil, made from steel refined in a gas fuelled furnace (or maybe coal fuelled, but the trains that carry the coal run on diesel). The workers wear clothes made of polyester (a plastic), and get home from work by driving their cars (powered by gasoline) with tyres made of synthetic rubber on roads made of asphalt/bitumen/tar. They cook their dinner (vegetables grown with fertilisers and pesticides made from oil, and meat fed from fertilised grain) in gas ovens, and eat it on their varnished dining table on their laminate floors in their painted dining room. They watch TV made from plastics and petrochemicals, powered by electricity which is made from burning gas. They remove their make-up and wash themselves (cosmetics and cleaning products both being largely from petrochemicals). They go to bed under their cotton sheets (the cotton having been fertilised, harvested using diesel powered tractors, spun with electric motors, transported, dyed and packaged) and read about how the evil oil companies force their oil upon us in their book (which has been made by being cut, transported and milled into pages, and the pages bleached, printed, and shipped, all of which are powered by...)
Like I said, I can't think of anything tangible that doesn't depend on some way on oil.
Maybe you don't know what a petrochemical is - you've never seen one or bought one so you think you've never used one (all you know is that 'chemicals' and 'industry' are ugly and smelly and bad) but industry exists to feed our personal consumption - the end product of all these industrial processes is always something personal, something that we think is going to enrich our lives.