No large ones, but (101) amazingly assorted small extension and compression  springs -- most, but not all, 1" to 2" long. You might even find a stray torsion spring! Assorted lengths, assorted widths, assorted finishes, a sorta handy bag of replacement parts to have around the house.

Your ordinary generic everyday plain old steel hinge measures 2" long x 1-1/2" wide when open with a 1/8" axle and mounting holes just a hair under 1/4". Comes with screws, as they will. Ordinary, yes, but necessary.

These Bulldog Hardware steel gate hinges are black and measure 4-1/2” tall. Outside plate is approx 3” square with a slight taper and (4) 1/4” bores. Inside plate is 4” long x 1-3/8” with (4) staggered 1/4” bores. Hinges swing 270 degrees for fully opened gates. You’re going to need at least two unless you're making a cat flap.

You could fit all of these springs in the palm of your hand, but they're still mighty handy. Steel extension springs, 1/2" long x 3/8" dia with 5/16" ID loops at each end.