Dreams draw mostly from your own memories, but it’s still entirely possible for completely new things to arise within them. I once had a dream where I fought my way through a hoard of undead dinosaurs using a pair of antique pistols in order to escape a vacuum-sealed mine.
I only wish I knew what part of my mind that one came from.
Edit: And I would like to polite deny the assertion that dreams can predict the future.
Pretty much anything can be made in a dream by taking even individual pieces of objects from your memory and combining them to make things you think you’ve never seen before.
Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valve’s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.