A GUI for Mozilla SOPS to use it as a password manager.

GUI for Pipewire configuration. Being able to reliably change the sample rate and buffer size without having to mess with config files would be nice.

Three finger drag in Wayland, a new gui for opensnitch where i can isolate network activity by app like little snitch 

GUI for managing fingerprints/PAM that allows complicated or at least some customization with PAM such as requiring password on first login then allowing graphical fingerprints for sudo, unlock and other prompts with fallback to password.

Qt version of cool GTK software: Nicotine+, Ardour (ahahah), Lutris, Cartridges

Qt software I would love to see graphically improved: QuodLibet, Falkon, Qbittorrent, KeePass

Others: PeerTube client, Syncthing client, Ardour+Kdenlive fusion (a good Video DAW is my wet dream), Lemmy for desktop

I don't have a concrete idea for you, but I suggest starting with something really simple. I think simple games are a good place to start. Or create a front-end for some command line tool to make it easier on beginners. That way you can focus on the UI development you're interested in without getting bogged down in the rest of it.

I wish Scratch was more powerful, kind of like Flash was back in the day, so that it would be easier to make more complicated things with it. I feel right now if you want to make a somewhat real game it gets too hard too quickly because you need to work around the limitations.

WinSCP is a Windows tool I use at work to send files between machines and I wish there was linux version. Programs like Dolphin are similar but I always manage to find something I can do in WinSCP that I can't do in the linux alternatives

Edit: commenters just pointed out a bunch of potential solutions I wasn't even aware of, so I'm probably just dumb please carry on

• Bulk unarchiver or a frontend for ffmpeg (using existing tools, both get very messy when special characters or multiple directories are involved)
  • Existing ffmpeg GUIs have had fixed lists of formats and options, making new or obscure ones inaccessible. There also needs to be an option to export the command based on GUI selections so the user can learn if they choose, or fix the command if something isn't right.
• Adding the little details of Windows File Manager (i.e. Format dialog, search by attribute like MP3 bitrate) to some existing Linux file manager
• Mounting of network drives in Linux graphical file managers: many of them handle it through gvfs, which for some reason insists on mountpoints with long directory paths and special characters, breaking compatibility with various utilities
• Extending Linux Mint's libadapta to further restore theming in libadwaita apps. This I am personally looking forward to contribute to as more programs move to libadwaita and disrupt the look I've painstakingly set up for my desktop.

I wish Divvy/WinDivvy worked on Linux. There are similar alternatives, but none that duplicate the functionality.

SSH connection/session manager for people who need to keep lots of open connections to different remote devices, like Xshell for Windows. There are options for Linux that come close in functionality but most seem to miss one desired feature like vertical tabs, grouping connections with a one-shot open of all in a group, saving/restoring sessions which keeps all tabs in the same order, sending keystrokes to all tabs in a window, or split panes.

Tabby is the closest I’ve found so far and is pretty nice overall, but it’s missing some functionality and isn’t the snappiest being an Electron app.

Streamlined VM deployment inside a headless server. Been scratching my head for 2 days now on getting a Debian VM to work as advertised. Every step of the way I keep thinking "surely it doesn't have to be this difficult, right?" And for some reason, a basic netplan edit to make a bridge broke all my NFS binds. Took all day to sort a brand new permissions issue that shouldn't be possible

After Dark Totally Twisted - The Grossest, Goriest, & Weirdest Screen Savers from Berkeley Systems: https://www.youtube.com/watch?v=D0dD_TACPx0

They don't have to be graphical but there are some things I can think of that I'd really like to have or see improved.

Some form of an app that will allow me to get the most out of Flathub. I know that I wont use every app that exists on Flathub but I would like to have some app that will allow me to at least see every app that's available. I don't care if it's something as simple as just a list of every app in the order they were added, preferably sorted/sortable by oldest first and multiple pages to make it easier to find where I left off, or if it's something more intricate, like a full app store experience with an app recommendation system that filters out apps I've already interacted with.

Something will allow me to get better use out of GameFAQs, I was thinking about something similar to Anime Plus but for GameFAQs. If you're not familiar with Anime Plus, it's a companion app for My Anime List that creates a temporary profile based on your MAL account and gives you a list of anime/manga that are missing from your account and gives recommendations for new anime/manga. If that's not possible, similar to Flathub, I don't care what is made for it. Right now, I've been using documents to keep track of everything but I noticed that this isn't reliable because there is no way to be notified of when new games are added since games are only sorted alphabetically.

I feel like there are more things but I can't think of anything else right now.