I am not aware of anything in the 1/4" size. 1/2" is available to a limited extent, often for pet collars.
You could try mitten hooks, bungee cord, mini-cord locks, ...
For a quick release connector, you can try this. Make a short loop of string for the buckle. Tie a figure of eight knot in the bungee cord. Slip the bungee through the loop and let the loop catch the knot. It works, but is not really adjustable. I have used this to hold an ice axe on my pack instead of the cumbersome buckles.