Go bags could be just about anything that you can carry stuff in. That does not mean a paper bag is a good choice for a go bag. If you are putting stuff in the bag you expect to keep you alive, you want something that is sturdy enough to take a beating and constant use.
It should be light enough to carry so that it will not kill you by slowing you down so much that you can not get to a safe place when you are carrying it.
It needs to hold your life-saving items securely. It needs to have strong straps or handles that will not break easily.
Your go bag will be more useful if you can find whatever you are looking for inside it quickly. It would also make it better if it is easy to pack and unpack. That can mean lots of pockets or containers inside to organize the contents. Containers and pockets can add weight and you need to be able to tell what is in the pockets and containers without opening a lot of them to find something. Some kind of marking or labels for the contents of pockets or containers may be a way for you to know where things are. A map and checklist of the entire contents of your go bag may also be helpful.
You need to decide what type of go bag you want. Do you want a duffle or sports bag type? Do you want your hands free with a backpack? Would a wheelie bag be any good? Will it need to go over ground where the wheels will be a problem? Does your evacuation route have good sidewalks all the way? How much do you need to carry? How heavy are the contents of your go bag? How strong are you and how much can you comfortably and safely carry?
If you have children and pets will you have separate go bags for each of them? If so, what kind of go bag will you need for each of them? They have small backpacks for tiny children. The rule of thumb for backpacks for children is a maximum of 15% of their body weight in a backpack.
They do have backpacks for dogs and some people take their dogs hiking and let their dog carry their own food supply and bowl, etc. This sort of backpack would be ideal for a pet's go bag. Preparation for the pet's backpack is necessary. They don't universally take immediately to carrying a backpack and will have to be trained, to take it as a matter of course or even like it. If they think of wearing the backpack as a prelude to a fun walk, they will be cooperative when you need it in an emergency.
I have not yet tried a backpack on my cats, but am thinking about it. They do tricks and learn new things constantly, so I expect it can be done. I have trained cats to walk on a leash before. A leash would probably be necessary to evacuate cats if you want them to carry little backpacks. A caution here is that emergency shelters for pets require them to be in a carrier or on a leash and they must have proof of vaccinations and licenses etc.
If you practice carrying a backpack or other go bag, you will be able to carry a heavier one and handle it better. It is a good idea to practice with a weight that is equivalent to the contents of the go bag. The same is true for your entire family.
Ok. Now go out there, get your go bag, fill it up with the items you have selected and practice carrying it! Once you do that, you and your family are that much safer and ready for emergencies.