My last parent passed away, and I’m dealing with the estate/inheritance. I was the close child and trustee/executor (personal representative). It’s a miracle that all the siblings are still friendly (though there is still money to be paid out)! I will also warn you that it is a LOT of (thank-less) work.
One of the projects was to sort out all of their keys. It was no small task, as my father owned his own business. I also decided to do my keys at the same time. I’ve tried to hit all the points, but it is hard to organize this topic because of all the subject overlap.
The key sets that I have made include the following:
Master Key Set: These keys are on a big, loose-leaf-paper-binder ring  so it is easy to open and get a set off as needed. I used colored (though color does not mean anything for my system) plastic key chain tags , labeled with key group for different areas/people. It is w-a-y too big to fit into a pants pocket. I did not label each key as that was too much work. Each key group has a quick-clip, so it can be attached to another ring or somethig else.
Master Key Set 2: A second set is kept at a remote location. It is on a big split key ring . This set has the keys grouped in areas/people, but it has no tags and is not labeled. It has a chain and belt-loop clip.
Guest Set: This set of keys can be loaned to a guest to get into our dwelling. It has a quick-clip to attach to the guest’s keys easily. It is also big enough to hopefully remind the guest to not take our keys when they leave.
My Set: This is a minimalist set. On this ring, I have a mini-flashlight  that I use a lot. I put it on a 2-1/2 inch chain from the hardware store so when I put my keys into my front pocket, the flashlight hangs outside my pocket. When I want my keys, I grab the flashlight, and pull the keys out. This way I don’t have to fish in my pocket, and it keeps the keys from balling up into a wad in the bottom of my pocket. Included are a regular and Phillips screwdriver (I still have not found something that I really like) and other keys I use often.
Since I have an old pickup, I keep two pickup keys on the ring. One key is on the main-ring, and the other key is on a removable clip (like a carabineer) in the center of the keys. This does two things. When going somewhere, the pickup key hangs below the other keys, so I can get to it without hunting for it. The other is, well, because it’s an old pickup, it needs to go into the shop, so I just unclip the main key and leave it with the mechanic. The backup key stays on the ring, and if I need to get the truck after-hours I can have the mechanic lock “his” key inside the pickup.
I also “ordered” the keys on my ring. One side has Dad’s keys; the other side is the apartment keys. On one outside/end is the apartment door key with one of those plastic rings  around it. The plastic ring allows me to feel which side/key is left and right. Inside of this key is the building door key. This is especially important, because like you, I always seem to be carrying way too much stuff, so this ring enables me to quickly feel my way to the key I need in the dark.
Hidden Set: We are not perfect, and mistakes happen like losing keys or locking keys inside. Maybe the power is out and the garage door opener will not work. It may be wise to keep some type of key(s) hidden so you can gain access to _______ when you have nothing. There are a lot of places to hide keys. Be inventive; don’t just buy the mass-produced rock from the hardware store. A two-step approach would be to hide the key to a shed somewhere outside, and hide the house key inside the locked shed.
Wife’s Set: Well, what can I say; she does her own thing. Might I say, she seems to need to carry everything in that purse of hers.
Bug-out Bag Set: These are yet to be completed.
Traveling Key Set: I have just started making a set for traveling, because I miss my flashlight and nail clipper/file. Everything needs to be able to go though airport security. I’ll need a house key and a vehicle key, but all others can be left behind.
Other Key Sets: These are for various people or places.
Extra Spare Keys: These were grouped and labeled with a tag (white cardstock with the metal ring around the edge). These were then put into rough groupings in a parts organizer  with lid (from home supply store)
KEYS – PHYSICAL – LOCKS
Grouping physical keys can be a challenge. I grouped mine as follows:
Dwelling: front/back door, dead-bolt, garage, shed, inside doors, safe, file cabinet, et cetera
Vehicle 1,2,3: door, ignition, glove compartment, gas cap, hitch lock, et cetera
Camper: door, cubbyholes, hitch lock, bike lock, et cetera.
Equipment: boat, neighbor’s lawn mower, snowmobile, tractor, golf cart, trailer, scooter, toolbox
Other: safety deposit box, gym/locker, storage unit, padlocks, pop machine, games, dog kennel, cash register, desk, cabinets, luggage, paper towel dispenser, outside hose bib, farm gate, mailbox, skis, audio visual, musical instruments, copier, bathroom, firearms, et cetera
Organizations: church, Boy Scouts, volleyball, PTA, et cetera
Parent 1,2: _____
Sibling 1,2: _____
Child 1,2: _____
Friend/Neighbor 1,2: _____
KEYS – PHYSICAL – DIGITAL
These “keys” are physical but not to traditional locks. They “unlock” something using data through something physical, such as a magnetic strip cards. These include credit/debit card, calling card, COSTCO membership card, employee/work badges, cash register key, USB Key, SIM card, et cetera.
KEYS – PHYSICAL – BIOMETRIC
These “keys” are physical, but again do not unlock traditional locks. They are usually electronic in natural and are unlocked through biometric identification. For example, my nephew uses his finger (print) to unlock his phone.
KEYS – PHYSICAL – RADIO FREQUENCY – “KEY-LESS”
Here, I’m referring to auto FOB. While the Internet says fob is an old-time term for an ornament on a pocket-watch chain, I’m referring to the transponders that emit radio frequency to “unlock” or activate an automated door; these might be a garage door opener, work badge, and could include infrared controller for the TV remote, and more.
KEYS – NONPHYSICAL – INFORMATION BASED
These “keys” are basically codes, such as username and password. Much, today, is accessed though non-physical keys, often in the form of “username” and “password.” Some people handle this by letting an ap/application (software program) keep track of all this information. If the electricity or Internet goes down or the device is lost/stolen or computer crashes, or someone is injured or passes away, then it is a lot more work to retrieve this information. One way is to write the information on a key tag and keep it with the keys. Do realize that anyone who looks at your keys could then have access to coded security items/areas. A simple back up is just to use 3×5 cards to record the information. Some coded items are:
- House security system/lock, thermostat password, TV child lock, and garage door code
- combination locks, gun locks, and electronic safe locks
- PC login and logins for games, e-mail, social media accounts, and anti-virus,
- bank accounts, brokerage account, credit/debit card and associated PINs, government benefits, PayPal, et cetera
- Amazon, E-Bay, newsletter/subscriptions, and NetFlix account logins
- membership numbers to AAA, SAMS, and others
- medical/emergency equipment i.d./access numbers as well as SSN and birth date for admission to a hospital
- phone/Internet provider, cell phone, audio equipment, answering machine code, and PDA
- license(s), license plates, and passport (although not a key as such, might be good to know the numbers)
COMMENTS – OTHER
Everyone is different, and you will have to figure out what works the best for your situation.
My wife’s car has a fob. The 2nd fob is kept on the Master Key Ring 1, and I only take it with me when we go on a trip. I should buy another, but they are expensive. Hiding a spare fob on a car is difficult because water can kill it, and sometimes the car can still detect the stupid thing and allow entry. I’ve heard that a waterproof container and wrapping it in aluminum foil should work.
I keep a padlock with the pickup, and the key on my key ring. I have a log chain in my pickup for pulling things. When I have bigger equipment in the bed and the truck is not attended, I will padlock the equipment with the chain.
Be aware that not all key chains/rings are made the same. If you are going to carry it, it has to stand up to a lot of abuse. My fingernail clipper fell off; for me it was easy enough to solder the small chain link closed.
Some items have renewal dates. It might be efficient to gather this information at the same time.
The fobs and other digital items require good batteries, and some things above may require directions for others to operate.
Banks typically ask for the mother’s maiden name as an identity verification/password, but realize that this is public information. You may wish to use some other name/word.
Keep in mind that there are some tools that have the same function as keys.
Keeping your garage door opener in your car is not totally safe. If anyone gets into your car, they will have your house location (auto registration) and your opener.
I used an electric engraver  to mark some keys. It has a pointed tip, and works kind of like a woodpecker. It was simple and effective to use, and it will never wash off.
I bought some items from Amazon, because it was taking too much time to run around and find what I wanted. Keys are often for honest people. In the Bible, Psalms 127.1b “…except the LORD keep the city, the watchman waketh in vain.”
If a set of keys are lost or stolen, you will know what locks need to be changed. So, keeping less keys on the ring might be less convenient but a better security choice.
We will die, and all our stuff will go to others. This is a huge topic in itself, but a lot of the above information should be made known to the man/woman who will handle your estate when you die. When people are going to die, they seem to know it at some level in their soul. As such, the worldly things become value-less to them. For example, my father threw away his hearing aids, billfold, and, yes, his personal keys have never been found.