I'd want to learn how to crochet so that I could make amigurumi and see if that could be a side hustle for me, or at least so that I could make my own plushes of my OCs.
I just don't have the time to try and learn a new skill rn. 
Animation is something that I've always been very interested in, but have yet to find time to try out.
Ditto on wanting to learn to play guitar better. I own one and have played a bit here and there but if you asked me right now to grab it and play a song, I wouldn't be able to remember any lol.
trying my hand at making some youtube content has been on my mind the last few months, but I have yet to find time to sit down and try recording anything lol.
For the animation bit, I might try my hand at that this year, actually. I started a Twitch channel last year and wouldn't mind making some like... 3 second animations or something for my alert notifications instead of using the generic stock ones like currently xD
Youtube is something that I want to try and find time for this year too- even if I can only make a couple of videos, I think I can piece something together over time~
Sadly I don't foresee having time for music any time soon though... ;u;
If my comic could be an animated series instead, that would be the best. I tried animating a movie (I started when I was 14 and didn't know any better) and in five years of working on it, I only got one 10 minute part finished.
I'd also love to learn how to sew and dabble around with fashion design. I just feel like there's a steep learning curve at the beginning that takes too much time to overcome.
I would love to make an epic 500 page comic. But currently, I'm too slow, I'd burnout after a couple years.
Or, I'd like to make a scrolling comic, but again, it takes too long just to make one episode.
I would love to get back into sculpting, crafting and sewing. I was an ok sculptor and seamstress in my teen years, but depression + college happened, then I got a ton of health issues that limited my working time in a day to only a couple hours (my hands would swell and hurt if I did more than that). My hands are recovering now, but because it's a nerve issue my proprioception and small movements just aren't there. I'm reasonably confident I can work at least some of it back, but... I need to recover more and reduce the nerve inflammation further.
I would also honestly love to draw another comic. I'm fine with my current pace on Engram. I like being able to just work on it for 2 hours a day and leave it alone if I don't feel like it. But that does mean that if I HAD the health for it, I could easily do a number of other story-telling projects - for variety. But, again, I don't really have the health to draw for 7 hours a day. I HAVE made some small movements to start working on my book again - just aiming for a few hundred words or a scene a day for now.
As of this moment I have 8 ideas for novels... and the list always grows, no matter how much I write. 🤣
Fashion design. I can sew very basic clothes but I would love to make more complex pieces.
I wanted to make a channel showing how do we make our toys, custom painting, wigs, reviews but that's literally a part time job. 
I do need to find the time to practice anatomic drawing. 🥺
ahhh so many things! I have other comic ideas and would want to get back into sewing. I used to sew in high school (mostly plushies) but don’t really have the time now.
I'd love to start some kind of either podcast or YouTube channel and do (video) essays or discuss some current topics and struggles in online art culture and the community sorrounding it... I'm actually kinda looking into it but it's gonna be a while before me and a friend who I've asked to co host will be able to look into it.
Also, this isn't exactly ~creative~ but I wish I had time to take language classes in Polish and Russian, but I can't because 1) masters degree isn't gonna take itself, 2) im exchanging to Czechia and I want to learn a little basic Czech before then 
i was just thinking about this earlier today!
I'd love to learn an instrument. Between my job, disability, living, drawing, and doing a comic, I don't have time to out in all the time needed to practice playing. I have a ukulele, but I just don't have the motivation to learn or develop the callouses needed to play. Ah, if only I didn't sleep 12 hours a day!
I'd love to work on longer YouTube videos or just videos that require me to make several art pieces. I can sometimes work on them, but that's rare.
I've had a detailed plan for an animatic kicking around on my computer for nearly two years and I just haven't found the time so actually make the thing. And now, with my focus being on Blue Star Rebellion rather than its parent project (where the animatic is from), there's not much point. 
I may come back to it in the far-distant future.
Ooh if I had the talent and resource I'd want to make a web series XD Maybe of my comic or one of my fanfics
I also have an idea for an RPG game potentially... and a visual novel lol
I wish I could take up music again. It was my major in college before I dropped out and was also my dream in life. I still have both of my keyboards on me and my books but I just... Really haven't had the time or motivation to do it anymore. My creative time is spent with doing commissions and comics, and my other time is spent at my job.
I think someday when my voice drops from taking testosterone I might finally feel comfortable with my singing enough to work on songs again. That's one of the other main reasons I stopped pursuing music.
I'd actually love to create quick animations of my characters and of some of my comic pages as well, I've seen a lot of people on instagram animate their comics and I'd really love to do that too, the only thing stopping me is not having enough time or proper resorces.
I'd actually want to adapt my novels into real graphic novels. No floppies, but actual big books. I think that'd be really cool. If anything, I'd also possibly want to create sculpted crafts. I think that would be wonderfully fun.
Indie games. They never make any money and I'd have to learn to program, but experimental interactive narratives using video game engines is something I am extremely interested in... and I'd do it if I had any time! But this kid's gotta put steak on the plate.
Also, fan fictions. I haven't been able to make the Glory of Bowsette sequel that people have been clamoring for since 2018, and there are some bigger projects that I'd love to do while playing in someone else's franchise. But I'm already too busy for my own projects, so those get put on the "maybe when you're writing full-time as your sole job" back burner.
ALL OF THEM.
No but seriously. I love to write short stories/poetry, I have always wanted to try out a visual novel. I think the main thing, honestly, would just putting more love and time into my current project. It was a leap of faith to take in the first place, but I know I could do more if it wasn't my nth priority. I'd also have more time for extra content like bonus comics and patreon rewards.