2.My Recording book
I have a long hard shelled book that i use for keeping records of all the airdrops and bounties i promoted because sometimes i used to forget easily so i write down my recovery seeds in this book as well
3. Flash Drive
I have a good 8gig flash drive as well that i use to copy software and files from one pc to another so i format this flash drive and copy my private keys and recovery seeds in it.
This is the best method on what you listed this two will really help a lot if you can't afford to buy a hardware wallet like trezor and many more plus this is the method that I'm also using to keep my passwords and different private keys for my accounts. I can't totally recommend the hard drive method because a hard drive can easily be corrupted (base on my experience).
I agree, I once experience to save my wallet in my hard drive and it was corrupted where I cant recover it anymore. Buying a hardware wallet is better, its not that pricey to even spend a little for the security of our investment. It is for our own good and it wont let you down once you store funds in it.
You can also use google drive to store private keys, and the list of the projects you become part with, it is safe because you can enable 2FA to secure your drive.