You can't randomly generate a base-58 WIF private key directly because some of the bits contain non-random data. So you are going to have to generate a random 256-bit value and convert the result to a private key. Also, keep in mind that not all 256-bit values are valid private keys.
Basically, the number of N-sided dice you must roll to get 256 bits of entropy is 177.446 / ln N.
Do you know where I can read up on entropy? I'm not sure what that means or how to calculate it.
Any other simple/quick entropy sources would be welcomed as well. I'm just trying to save myself some time when generating private keys for cold storage and I don't trust other entropy sources since idk where they get it from or how it works. Thanks!
How about mouse movement? I seriously doubt it can be "recreated" easily since there are many factors from mouse type, DPI, mousepad surface, user's mood & many more.
The only problem is understanding library which used to generate entropy & you generate it while you're visiting website which track user's mouse movement.
Do you know how would I record mouse movements and/or how could I could use that as an entropy source? I know bitaddress uses this method but then at the same time idk if it's using JavaScript cryptography, which isn't secure enough for a Bitcoin private key IMO.