| Oh, Leader! | Math/Prog Metal | Gipuzkoa | |
| Oneiric Delusion | Heavy/Prog Metal | Bizkaia | |
| Orihen | Rock/Metal | Bizkaia | |
| Orion Child | Dark Power Metal | Bizkaia | |
| Ossyris | Power Metal | Bizkaia | |
| Ostots | Black Metal | Bizkaia | |
| Our Natural Killer (Onk) | Metalcore/Hardcore | Bizkaia | |
| Overloud | Hard Rock | Gipuzkoa | |
| Oxida | Death'n'roll | Gipuzkoa | |
| Oxido | Heavy Metal | Nafarroa | |
| Ozki | Doom/Sludge metal | Gipuzkoa | |
| Patxa | Heavy Metal | Bizkaia | |
| Patxi Luque | Hard & heavy | Gipuzkoa | |
| Perseveranth | Heavy Metal | Araba | |
| Pestilength | Black/Death/Doom Metal | Bizkaia | |
| Pi L.T. | Alt Rock/Metal | Bizkaia | |
| Positiva | Hard Rock | Bizkaia | |
| Prophetic Scourge | Death Metal | Lapurdi | |
| Psilocybe | Thrashcore | Araba | |
| Punto Muerto | Heavy/Thrash Metal | Gipuzkoa | |
| Quaoar | Prog Rock/Metal | Bizkaia | |
| RAS | Grindcore/Death | Gipuzkoa | |
| Rass | Reggae/Rap Metal | Araba | |
| Ready Aim Fire | Hard Rock | Bizkaia | |
| Reditio | Rock/Metal | Nafarroa | |
| Rise To Fall | Melodic Death Metal | Bizkaia | |
| Robert Rodrigo | Hard Rock | Bizkaia | |
| Rotten Notes | Death/Grindcore | Araba | |
| Sabotaje | Heavy Metal | Bizkaia | |
| Saddict | Metal | Lapurdi |