Killing blue dragons in taverly dungeon for hides/d bones is very good money, but its risky i've been dds speced out 2 times there.
Also i wc and fletch yews south of falador, this is really good rebuilding money for me as i have a rune axe in bank and can easily get like 100k in 30-60mins for a fast rebuild after i die.
You can makes yew longs and alch them for a profit aswell if you have the patience for some free cash + mage EXP.