Suggestions

There are several ways to own an item, but to not have it in your Hoard or Vault. While some steps have already been made to make it clearer when you already own an item, there's a few places where improvements could be made.

Marketplace
The Marketplace (both Treasure and Gem) has the best current support, with an icon to show an item is in your Hoard/Vault, an icon to show an item is applied to a dragon (familiars/apparel/scenes), and an icon to show an item is applied to your account (vistas). It is also possible to filter based on an item being in your Hoard and/or Vault.
It would be nice to also have the ability to also filter items based on whether it is applied to your dragons or account. This makes it easier to for example focus on apparel or familiars you do not already have, instead of having to go through the list of equipped items to find the actual non-owned things.

Grand Exchange
The various Grand Exchange stalls currently only have an icon to show an item is in your Hoard/Vault, but no option to filter out these items. Furthermore, the moment you apply an item to a dragon/your account, this icon disappears, making it impossible to quickly distinguish between items you have never bought and items that are applied to dragons/accounts.
A way to improve this would be to use the same solution as in the Marketplace, which is to add a second icon to the item listing, showing an item is equipped or applied. Additionally, the option to filter out items you already have would be great, especially as stalls get more and more inventory.

Baldwin's Bubbling Brew
Baldwin currently has no way to distinguish items you own from items you don't. It would be nice if Baldwin's recipes, too, could get some icons as described earlier, as well as more filter options.

Swipp's Swap Stand
Swipp also has no way to indicate you already own an item, be that in your Hoard/Vault or otherwise. It would be nice to have an icon to indicate that. Filtering is not necessary here, due to the small volume of trades Swipp has open at any given time.

Wishful thinking: Auction House
Like Baldwin, the Auction House has no icons for items you own, nor filtering options. Unlike Baldwin (and the other shops), the Auction House is highly dynamic, with literal thousands of active listings, which I can imagine makes it infeasible to check whether a player already owns the items listed, as well as to filter on that. It would still be nice to have those options, although it would in my eyes be the lowest priority. I mostly added the Auction House to the list for completeness' sake.

considering that iirc the grand exchange shops were a solution to the bloat happening in the marketplace for event items, i thought it was odd they didnt have the same search/filter options, nor icon types. i definitely support a standardized format for all those stated to match the marketplace!

i’d also would really like some icons for the game database where applicable, since i currently need to keep multiple tabs open for my hoard, dragons and the database entries to keep track of what items/apparel i do and do not have. those icons would pretty much solve that issue.

I support because QoL.

Honestly support, it really sucks when I go to sell apparel or familiars but I have to triple check if I have a duplicate so that I don't sell the only one I own [emoji=coatl deadpan size=1]

oh ya would have liked this if it was just one of the things that need improving, but all of the ones I can think of are here. it's annoying to have the icon not everywhere

Bumping this up to say I added Swipp's Swap Stand to the main post, given that that also doesn't have already-owned icons right now.

PLEASE, this has been driving me nuts in the Grand Exchange shops.

(You know, these things are never implemented overnight- the fastest turnaround time I've seen on a suggestion is around three months or so)

With the AH, I don't actually think it's a pipe dream. After all, you're only allowed to fetch up to 50 results from the server at once, yeah? So that should theoretically not be too much more load than a page of the Bestiary, which does have owned/on dragon filters. Dunno how it'd shake out in practice though.

(But also... I really hope Hoard can have some help here, I keep trying to apply Vistas I already have applied, heh...)

i'm bumping this for notn bc i almost forgot i had already applied some of the vistas available at higgin's shop and almost ended up buying them again, so it would be really nice to see the applied vista icon at the very least in the grand exchange!