I started with the Dominic System, but it wasn’t ideal for me, because I don’t like having too many people in my images.
As another example, here’s the system that I use: A 2-Digit Consonant-Vowel Number System (CV System)
It’s a combination of the Ben System, the Major System, and my own customizations.
Examples
The number 00 is pronounced “SO”. You can use any word that begins with that sound: sewing needle, sofa, soap.
The number 36 is pronounced “MIH”. Example words: mist, mitt, Mini Mouse, mimosa, millipede, Mick Jagger. (Using people is okay, but not necessary.)