I've had great success with a lined bag that had width to it as well.
Essentially just a normal bag but a square cut out each corner so it's this shape.
Two of those and then you just stitch together round the top with the handles in. You can even fit a big magnetic popper or a zip at the top to turn it into a beach bag.
Bunting is easy and fun if you have that sort of house.
A Zigzag stitch on felt can make some nice Holly leaf Christmas decorations which you can bend.
I'm also a big fan of hand stitched felt Christmas decorations (maybe a suitable Segway into other crafts?) Photos also attached. They're fairly simple but if you make the embroidery more complicated they do take a bit longer.
You could potentially produce some lovely Christmas garlands with e.g. felt holly leaves on ribbon, or little thinly quilted stars or something.
Christmas stockings wouldn't take too long.
Evening stoles made of velvet and satin, perhaps not very practical though!
Aprons to use in the kitchen.
I have a really handy drawstring bag for all my chargers etc for travelling.
I think a jewellery roll would be quite achievable in a few hours.
Sewing a summer dress only takes me about 3-4 hours if I start with the pattern pieces already cut out. I cut large, pin it on me and don't usually both even tacking though so I am probably a terrible example.
You could also do small patchwork projects in a few hours - things like needlebooks if they have a more complex pattern, and if it's just squares maybe something like a table runner (but probably only with precut squares for it or it takes forever).