A word of warning. You will find, if you look at the descriptions of the various inks which are waterproof or resistant, that many have caveats about their use in fountain pens. For example, Diamine Registrars is an iron gall ink, which can play merry hell with nibs and internals. I have myself spoilt a reasonable pen or two over the years through failing to observe the requirements arising from use of some waterproof inks.
There are various recommendations around the web. The procedures for preventing pen damage are mainly concerned with washing the pen out, and not storing it filled or unwashed. The other thing is not to use them in valuable/valued/vintage pens.
This site gives a reasonable run down of the inks which they sell (no connection, I should add):-
http://www.thewritingdesk.co.uk/reference.php?id=50
I personally use Platinum Carbon, which is a good ink, but needs the pen to be properly used and maintained to avoid damage. I use it in a cheap adapted Jinhao pen, which I do look after, but, if I forgot to "do the needful", wouldn't be an expensive write-off.