There is more than 2000 particle effect in the game. It takes time to find the one you need, I would like to share this script hopefully making it easier
Download and installation from HERE. It supports keyword filter and scaling.
what command have you tried exactly? for example, if you wanna see all particles contains the keyword “firework” at a scale of 0.5 of their predefined size, just type /particles 0.5 firework in chat.
For more detailed information, check out the Usage section on GitHub.