You are stunningly unlikely to find "what you are looking for" (certainly not form-factor-wise) in equipment that is listed for connection to mains voltage. There isn't physical space for the required safety factors in insulation, etc.
However, 2 4-gang switch boxes, or one 4-gang switch box with duplex switches could do what you are trying to do in a listed manner, if properly connected.
There may be other products that can get you closer to what you want while still staying on the right side of UL (or other NRTL, depending on where you are on the planet) listing and code (whatever applies to your location) - DIN-rail stuff that's less common but still available fully listed here (very common in machine controls, even though uncommon for household power distribution locally to me) might be more compact. Elsewhere in the world it's the normal household power distribution already.
Obligatory need to point out that code (whatever code applies to your location) is "written in blood" - they want things done a certain way, or parts to pass certain tests because people died from NOT doing it that way. So follow it, even if you don't understand it (and try to understand it, since that will make following it easier.) Line voltage is not the same as being on the far side of NRTL listed low voltage supplies.
Note: if the coils of your relays are low voltage, you can probably just control the coils directly, rather than having "bypass switches" on the mains side of things. Of course, your relays need to be suitable and listed for mains use themselves, and low-voltage controls need to be separated from mains voltage by physical barriers.