Hey there,

I was thinking of reading more fan fiction as reading material, but apart from scattered fan sites, having trouble tracking down any nice amount of it.

Could there be a good website archive?

Any tips for finding? Thanks much.

By fan fiction do you mean any amatuer writing, or do you want stories based on published works? If it's just amatuer writing then http://chaosparadise.jp/ has loads.
I also have http://onlinenovel-reader.hanameiro.net/index.php?Index in my bookmarks, though I'm honestly not sure what it is. It must be there for a reason though, and it seems like it might be relavent.

As far as I know there is no archive in Japan like Fanfiction.net, so your best bet to find anything is to just type 小説 (that's what they call FF in Japanese) and a pairing name (like サスナル or whatever) in a search engine.

But a lot of those individual sites are also compiled in ランキング or 小説検索所 sites, so you might find more if you look through those as well.