25 Jan 2010 at 21:10 - 9
tl;dr? - No, sorry, no list. Use search to PC if you can and/or spend some time asking other players.
My standard way-more-than-you-wanted-to-know-or-read response ...
Over the years I've watched a few people with nothing but the best of intentions try to write such a list. I've never seen it work nearly as well as the ideal you're looking for. In this thread you have some folks doing their best to give you a quick list, but they can't cover everything.
You have to realize that a lot of what is "rare" shifts with where most people are getting most of their drops. What is "valuable" shifts with supply and demand. I can think of all sorts of things which seem at least semi-rare because I hardly ever see them for sale. When they go up for sale, they don't always wind up being that valuable because there aren't enough interested buyers to bid the average prices up.
There was a time when things like Colossal Scimitars and Elemental Swords were considered both rare and valuable. Shifts in the game put a lot more of each in the market and slashed the prices. Today they're worth less than 10% of what they were a few years ago. It's supply and demand.
There are A LOT of possibilities in terms of gear drops. The "market value" of drops reflects not only the skin but the functionality of their fixed stats. Blue, non-max, inscribable tactics shields with the right stats sell like hotcakes lately, for ~10x the price of their gold, req 9 counterparts or more. It's because there are a lot more buyers looking for PvP shields. Inherent items with fairly common/core skins but an unusually nice mix of inherent mods are another example - such will sometimes sell for significantly higher prices than the gold, r9, insc. versions of the same skin when players who like "oldschool" gear take notice.
(I put "fixed" in bold up there because I'm talking about stats which cannot be changed with components like inscriptions and sword pommels, etc. I don't recommend anyone who is asking for advice on player-to-player trading try to increase the market value of their drops by attaching components. On average, you get more gold selling the weapons and the desirable components separate. Some people who know the market and spend a lot of time trading can manage to make better money selling modded gear, yeah, but that's a whole new art to learn.)
While we might agree on average recent price ranges for some things, realize prices for the same item can vary a lot. Just because someone bought one for 50k last week does not guarantee you will immediately find someone willing to buy yours for the same price ... or for any price. It just doesn't work that way. Some people don't mind spending the time to wait for the good prices when selling and the good deals when buying; other people just want to get their player-to-player trading done fast and get back to the ways they want to spend their game time. The game has never had any support for automated player-to-player trade, and it likely never will. (Please don't misunderstand this as me starting another "in-game auction house" discussion. There's no point in complaining about it or asking them to add it yet again - if they were going to do it, they would have.)
For all of the above reasons (and probably more I've forgotten,) writing up a list of what gear is worth how much becomes a monumental task in the first place. If someone did manage to write it, keeping it up to date is an even bigger job.
Bottom Line - no such list exists which covers everything, sorry. If you're very concerned that you not merch or undersell anything of value then you need to spend a good bit of time watching the market, looking for PC info, and then looking for motivated buyers. It is most certainly possible to get the hang of it, but it takes everyone some time and effort to learn something new.
I find Guru's search these days works a lot better than it used to - put what you're looking for in quotes (for example, "Dragon Staff") and see what kind of hits you get in Ventari's. If you're still not sure, you can always ask for PC help in game or here in the Price Check section. There's no guarantee that you'll get answers, but it can't hurt to ask.
Cheers & GL!
Luny