Balancing the economy is hard, and I think PA generally does a very good job.
But there are items on the market that are completely useless.

It would be really nice if you could revisit some of these outdated items and get rid of them, make them stackable or something.

I won't be able to mention all of them, as there are dozens of them, but here are a few examples.

1. The most annoying item in the game: Black Spirit's claw piece.

When “mass of pure magic” became basically trash loot, this item became completely useless. You don't even need it to teleport to Aakman/Hystria anymore, because you can now see where a portal will lead you.
The problem is not that the item is useless… it is that it doesn't stack. Knowing how item prices can go from 0 to max on any Friday, there is no way I'm selling the ones I drop in Valencia. But since they are not stackable, I can't store them anywhere but the central market, which is cutting into the available weight.

Another issue with this item is that it has a NPC value of 0.

NA might be the only server that has a use for them, since there are more crons around that than anywhere else.

Putting sockets into costumes and heating a mass of pure magic is something the blacksmith can do. Let us sell the claws at NPC's or something.

2. Most Kamasylvia mushrooms.

Green pendulous Mushroom, White Umbrella Mushroom, White Flower Mushroom. 
What even is their purpose. They have been out for year but have absolutely no use.
You could add new elixir recipes that use them. Maybe useful defensive elixirs, as most of the existing ones are completely outdated.

3. Swaying Wind shard.

Swaying wind shards drop more often, but rumbling earth shards are the ones that are being used in celerity draughs.

It would be nice if we could exchange swaying shard for rumbling shards and back.

I bet there are like 10 million of them lying around in storage, collecting dust.

4. Resplendent Jade / Resplendent Obsidian

I don't like calling thing dead on arrival. But when the new crates were made, you either made a mistake in which tier of the item goes into the crate, or you forgot to give these t3 items a use case, because they are completely useless. And you keep getting them by heating T1's into T'2s.

There are other weird items, like nolina, saffron etc. that just exist but have no use.

I guess this is not super important, I just wanted to point out that some of these items aren't just in low demand, but outdated and useless.

they could have just used the useless items as currency for the teleport instead of silver, that was a great opportunity missed by the developers

Like half of the items on the market are dead, useless items, that's hardly "good job", and despite the game have such bad economy since long time ago they keep adding more useless items with every new zone for no reason.

But it's just how it goes in most mmos.

There are no unnecessary items but the problem is:

- sick 35% market tax

- too low price of finished items in relation to the price of materials

- outdated and unbalanced crate trade and alchemy stones system.

I have millions of pieces of ore and timber that I have nothing to do with.

I know players still produce these crates but this is absurd. Currently mob trash is worth so much that all other ways of earning money give you pennies. Ore can be used to enchant alchemy stones but alchemy stones are outdated and their enchantment unprofitable.

Yeah these claws are rly annoying. Ancient creature's scale is the same.

Trace of chaos is just pretty much useless too. If that one could be used as a substitute in elixir of frenzy, there wouldn't be such a trace of battle shortage and trace of chaos wouldn't be useless.