Many years ago, the wife and I went camping fairly frequently. The first aid kits back then were almost useless so I made my own.
Starting with a sealable Tupperware box that was ~ 7" deep by 10" wide and 12" long, I put sterile gauze pads of various sizes in their own Zip-loc bags (qt. and/or sandwich sizes) and sucked the air out as I shut them. Generic bandaids of assorted sizes were treated in the same manner but I used those smaller "snack-sized" bags for them. I also put all 3 kinds of "tape" (paper, plastic, cloth) in for holding pads in place.
Liquid medicines (91% IPA, peroxide, iodine) were also sealed in appropriately sized bags (gallon for the IPA, snack for the iodine). Both "ace" elastic wrap and clean gauze rolls in 2-4 different widths were bagged separately as well as some cotton swabs, balls, and roll. In addition to the iodine, we also carried antibiotic ointment, NSAIDs, acetaminophen, straight & curved hemostats, needle-pointed tweezers, asst. length "stay closed" tweezers, a scalpel with replaceable blades, small, curved blade scissors, and 2 longer straight blade scissors(3" & 5").
Other than an occasional bandaid or gauze pad, we never needed much from this box except for the NSAIDs.