If you're only allowed to have one pedal, what pedal would that be? My answer would be Boss Distortion DS1 pedal. It's the most versatile pedal but also the most difficult to tame or set.
During the 90s, this is the only pedal I got and it wasn't even mine. I only borrowed it from my friend "Daboy." There was one time, during a battle of the band, where I was just pulled to join the band that I mentored and I don't have any gear that night. So I borrowed a guitar and borrowed an effects pedal. Guess who I borrowed the Boss DS1? My good friend Badong is a cousin of Barbie Almalbis and he borrowed the pedal for me. Barbie Almalbis lend me her Boss Distortion DS1. They were also joining the event that night. Barbie played Cranberries songs and Love will keep us alive by Eagles. We played Pearl Jam's Yellow Led Better and one composition and I can't remember what was the other one. I think it was Black by Pearl Jam because we were dubbed as The Pearl Jam of Capiz that night. We came second. Barbie Almalbis won first during that Battle of the bands.
To cut the story short, I fell in love with this Boss Distortion pedal. I used it when we play Smashing Pumpkins, Green Day, Guns n Roses, Pearl Jam, STP and other Filipino bands like Eraserheads, Rivermaya, Siakol, The Youth, Yano, Color It Red, Introvoys, After Image, Teeth, etc.
There are tons of good settings with this pedal. It's just finding that sweet spot between your guitar, amp and the pedal. Here's my demo, review and tutorial of this pedal. Hope you will pick up something from it.