Most of the links I have are ancient or I could be nice and call them 'classics'. I'd say start with Killa's site (http://seacouver.slashcity.net/) and work through there. oh! and the futures without end series of zines (http://mediafans.org/futures/) all of them now on-line. There is a real sort of division in fanfic between the methos-who-is-really-adam-pierson, the methos-who-makes-bad-choices, the methos-who-was-never-redeemed, the methos-the-eternal-victim and the methos-who-is-older-than-dirt-and-wiser-than-dumbledore. There's a lot of variation in how he's characterized, so it's hard to give good recs.