I do not know what list you talk about, but there is a feedback button on the left. That might or might not be visible, depending on your screen size. There is a feature request option.
Viewing post in Better collection management
I do not know how Itch staff processes those feature requests, but I would assume it is easier to have a single request for a single feature instead of giving them "a list".
And I disagree. A reverse order option for collections would enhance the usage of Itch for everyone using collections. It would make them usable as an actual watchlist. Without need to scroll to the back everytime you want to play the oldest game on your watchlist.
An exclusion filter is often lamented about in comments, but as someone who has ability to use a lot of different exclusions, I can tell from experience, that it does not give quite that enhancement. I just do not need it, and my project exclusion is so efficient that it can spoil browsing experience. It is one of those features that only look good on paper. (My project page has 3 different helpers to exclude things. And the most powerful can ignore accounts and games at the press of a button. If you weed out the top pages, they stay weeded out. A tag exclusion is misleading, since it depends on the devs using those tags in the first place. Also, interested users can find this in community and use a bookmark for single tag exclusion.)
I see. Then I'll submit first when an idea is shared. Though I'll keep the list for further discussion.
Also, I see your point in the exclusion filter. I suppose it's less about having a tag exclusion now. Maybe better filter result is what people need. (I've seen lots of people saying that they always find horror type games at first few pages.) This is something worth discussing yet kinda out of topic at this moment so I'm gonna stop here. Good point, though.
Oh it fits the topic. It is about managing the games to play. This includes saving them in collections for later, managing your favorites and finding new games to play, of course.
Maybe have a look here https://itch.io/t/3477347/add-an-option-to-exclude-owned-games-when-searching I have no idea why that thread has 8k hits. Probably scam bots posting there. Or a few people going there often to copy the code examples.
Excluding games you already have on your collection(s) is a nice idea. I thought, this is a thing I could do client side, and so it was. Was a fun learning experience and after learning about browser extensions, I thought, hey, it should be simple to make a button for the existing exlude feature that does exist. And so it was. Later someone inspired me that filtering genres would be super trivial and so it was. And I tuned down my extension for game filtering till it fit in a tampermonkey script, so it reaches more browsers. It will do collection filtering if you add your collection to the filter list.
It seems like this function works well for you. It'll be a great addition if it's actually implemented. Though it might be made into a kind of exclude filter if one takes their time to make a collection of games they don't want to see, which I'm uncertain if it'll effect the browsing experience or not. However, I see this function has more pros than cons so I'll request it anyway.