Ah, another Fritzism drag the 7805 on to the breadboard and click on that. Then inspector will let you change the options (but not I see to 12V!) in the Inspector window. Yes there are parts making tutorials
This is the latest series (and quite good)
and this one I made some time back as I struggled with parts creation which leads you through the complete creation of an existing part. (edit: it would help if I included the url …)
Part of the reason for the esoteric parts in Frtizing is because various companies (adafruit, sparkfun, the Arduino folks and various others) paid people to create Fritzing parts for their products. The other reason is that parts creation is poorly documented and quite difficult which makes it somewhat hard to contribute. Hope this helps as I want more parts too