First things first, collecting every unique item in Dwarf Fortress is impossible (or impossibly fun, depending on how you look at it) in several ways. If one were to truly collect every item, they would have to deal with the immense lag of all of those items, storage, the sheer number of years it would take, and so forth. What I am proposing is a toned-down version of All Items, one where the items need to meet certain criteria to be necessary. Granted, the number of items in both of my ideas is ridiculous, but it is much more manageable.
My first idea was to restrict the items to those with unique names, and even then only two or three different “factors” can be in the name. As an example, an apple wood barrel would be needed, but not a dwarven wine barrel (apple). Other “factors” are not considered either, such as the specific type of cut for gems.
My second idea was to depend on the stockpiles. In other words, if you can set a stockpile to only accept an item with a certain set of qualities, then an item with those qualities must be obtained. If this isn’t clear, all I can suggest is to take a look at what a stockpile can accept.
There are several problems with both ideas, however. As an example, the availability of items in a world are not always concrete. You would need in both scenarios to collect a cage for every Megabeast in the world, but what if even a single one dies before it makes it to your fortress? Randomness is a key problem anyways in Dwarf Fortress, yet one must heavily rely on it to complete All Items in either of my two ways for things such as the extremely important Strange Mood. Regarding Strange Moods, I wouldn’t be surprised if at least a quarter of the necessary items come from them. Perishability is another issue, especially for raw foods and certain caged creatures. I could list out so much more, but I’ll spare you the rest. At the very least, I hope you can understand that some specific mods would be incredible for All Items, in any form.
So, there’s what I have been thinking about very soon after I started playing Dwarf Fortress. Now, I ask for your opinion: which method is better? Both are absurd, and there’s no denying that, but perhaps these can provide a new way to play a game that was already not lacking in content. Also, if you have your own proposal, or you have some ideas for mods that would help this out in particular, feel free to let me know.
Am I doing it? Absolutely not. At least, not yet. As for anyone who does, have fun. Interpret that any in way you wish.