its easy to say the Rings cuz they already have that moniker but im thinking Cyborg's Omega Drome (when he still had it) in a nut shell it was a morphable armor that drew energy from another dimnesion that could create any weapon he could imagine....no matter how big, he could even create a cannon the size of a sky scraper , and the proprtioante energy needed to fire it if he felt like it ....without having to absorb surrounding material....just picture a more kick ass version of cyborg supes, or when guy gardner was warrior
that my friends is the most dangerous weapon
heres what i think
1. the spear of destiny{killed jesus, n could supposedly kill god}
2. saint of killer's guns{also killed a weakened god}
3. the heart of the universe{destroyed a multiverse}
4. infinite gauntlett{destroyed all abstracts other than lt as if they were insects}
5. the ultimate nullifier{destroyed eternity's twin, abraxas}