I went through that rabbit hole during the 2000s, when fuzz was my favorite effect, and the three pedals I've liked the most for stoner/doom were the DAM Meathead, simple and probably my all time fave for that application. This pedal is the simplest and most brutal Doom machine I've heard to this day. I still own it and still love it.
Next is the Pete Cornish NG-2 fuzz. This one you can set up more like a traditional fuzz face, heavy like a big muff, or out of control high gain Tone Bender MK-1. It's extremely versatile, and it has the famous Cornish buffer on it's input, so, if you use it first in line, it will help your entire signal chain tremendously.
Last of the three is the famous Big Muff Rams Head version. If you find a good one, it's really hard to beat for that application. Many players would opt to use the Green Russian Big Muff I had at my studio for Doom/Stoner, because it was bassier and smoother sounding, but would always pick the tracks done with Rams Head at the mixing stage, because they were more aggressive and cut through the mix much better than the Green Russian Muff.
Now, not a fuzz pedal, but one that I think it's a must for any Doom pedalboard is the Sonic Titan Overdrive. My all time fave overdrive for this application. Incredibly underrated pedal.
In my opinion, you already have the pinnacle of the Doom/Stoner fuzz, but trying new pedals is as fun as it can get, so, have fun on your journey!
