Heym .470 NE double rifle in the relatively affordable "PH" (professional hunter) model. Runs about 20 grand, give or take.
On a budget, a grand or so will net a CZ bolt action in .416 Rigby. Though you loose that quick follow up shot that might an important charge stopper that has been the traditional reason for having a double rifle when facing dangerous game.
On youtube you can see some videos of the .470 NE in action, such as - instead of shooting gallon water jugs - destroying a 55 gallon drum full of water. Should kill most everything and for a nominal additional sum, you can get add'l fitted sets of bbls in .30-06 and 20 gauge and just do everything with the same gun.
That'll keep any errant 'squatch from absconding with the Sunday insert and its lucrative Burger King coupons.
Do NOT use the .470 on gray aliens though. For them, you have to use either a special AP load in an FN 5.7 or else the hard to get black tip 5.56mm AP. Otherwise you have to get in close and thunk them with a .45 auto - or other weapon - that fires a subsonic projectile. It's a defect of their armor that it doesn't activate well against a subsonic threat since they designed it to counter their own energy weapons and hypersonic projectiles. Old slabsides will drop them every time though. Oh and don't touch the blood, it is toxic to humans. And yes, it is greenish, or at least becomes so when it contacts oxygen at the levels present in earth atmosphere.
You can also confuse them at time by shining them with the impulse from a TV remote control since they can see in the IR spectrum.
Vampires, they don't usually get up and around to steal a paper in the morning. Though I suppose with dark Raybans and SPF 100 it might be possible. Fire would work - it is the Biblical strength cleanser. Or a good sword to chop off the head. Or a 12 gauge blast to the face. But that works on most people and things.
Now werewolves might be more of a problem, since they love to chew up papers. Again, the flamethrower might work best, but if you don't have one, simply keep a coach gun by the door. Load it with shells using silver dimes as projectiles.
For Haitian voodoo zombies, try rounds loaded with Kosher salt. Yes, it has to be kosher. Or use fire again. Voodoo zombies hate fire.
For the other kind of zombies... see reference to 12 gauge blast to face or just use the Heym. Come to think of it, a .470 round works on most things too....