Vinay, here is copy of a response I made on another thread, some of it may be helpful.
one thing that can help out if you are concerned with overall size of the kit, you can tailor it to you particular vehicle. Most vehicles will not require a full set of sockets and wrenches, and those that don't fit fasteners on your vehicle can be left behind, this does require some advance knowledge or investigation of fastener sizes on your vehicle so you know what you can omit. Also beware that a lot of brands may have a mix of metric and imperial fasteners. Also there will likely be torx and other fasteners on modern vehicles. My Jeep has a surprisingly minimal selection of bolt sizes, at least in those that may vibrate loose or get damaged, I carry a decent selection of spare bolts and nuts of various lengths in those sizes and thread types, nothing worse than having all the tools and you are side lined due to a bolt that fell out or broken. I carry a ball peen hammer rather than a mallet because I feel like if i need to beat on something it will likely require a bit more force, the ball peen side is useful for rearranging dented sheet metal to clear a tire after an oops on the trail. spare fuses in sizes that fit, plenty of rubber gloves and a tube of hand cleaner, small tube of form-a-gasket and bailing wire are also in my kit. Organization of my tools is important to me, I want to be able to find what I need without digging through a dark bag, or dumping them out on the ground. Seems like its always dark and raining and I don't want to loose any tools. I use the Blue Ridge Overland tool bag, has 6 removable zippered pouches with windows so you can see what's inside, is expensive at a bit over $100 but very sturdy and a lot of tool space in a compact space. I also bring a small 4x8 tarp to lay on in an under the rig to minimize getting wet and dirty and to prevent loss of fasteners and tools when dropped. My personal tool kit does carry full sets of wrenches and sockets in all drive sizes along with some specialty tools because I have a lot of mechanical experience and find myself helping people work on their vehicles, so I put up with the extra weight and use of space.