Well then, for 90s tones you would need:
- Tubescreamer pedal. There are plenty of free ones. Check Mercuriall TSC (classic TS-808 emulation), this is probably the last TS pedal you will ever need.
- Distortion pedal. There are plenty of amazing free ones as well... check Mercurial MT-A (Metal Zone MT-2 emu) for that 90s shitty-gritty tones.
- RAT-type pedal. Nembrini Audio Black Distortion or
Valdemar Erlingsson Rodent are good free ones.
- Fuzz for that stoner/doom vibes. Bratwurst Fuzz and Linda Audio Fuzzy are my favorites here.
If you want I-dont-event-need-an-amp pedal, get Klirrton Grindstein from Audiority, this little beast can do everything metal up to swedish chainsaw.