Moon Rune applied to some sword enhances it. But I already used up all my Moon Runes.
Are there any similar artifacts or something that enhances the sword? Are there diagrams for creating them?

yes all the runes can be made
the diagrams seam pretty common

I think you can buy the diagrams for all runes from the dwarven blacksmith in Act I.

What about Chapter 2? Where can I get some Rune diagrams here?

where can i find rune diagrams in act 3?

Again, either the blacksmiths or perhaps the Mysterious Merchant (the DLC is free now, check my thread for links if you don't have it). If neither of them has the diagrams, then I doubt anyone does. Mysterious Merchant sells all the runes (he's got 3 of each initially), I'm sure of that, not sure about the diagrams.