We all know this. We need to do a specific task and with the help of the internet we find a specific tool alongside command line parameters to do the job right from the shell.
What is a good way of collecting/documenting these snippets on your own for future reference and use? Just a text file in the home folder?
spend more time in the shell. you will naturally learn the most commonly used commands and useful flags for them. soon you will be surprised by how much you know. having good typing speed helps reduce the friction a lot. i have not found need to specifically “memorize” anything consciously.
for obscure things, write a script and put it in a scripts folder, have a comment at the top explaining what it does for reference later.