I feel like the only way you could do those is if you added a space background but then what would you put for the things just a bunch of spaceships you got to think like you're the developer before you recommend things :)
Infinity: 1.79e308 Seconds (this also breaks infinity letting you get more then one IP next time) Eternity: 1e1000 Seconds (1e100 Centillions) Big Rip: 1e10000 seconds (idk what to say) Heat Death: Unlocks Heat (you can melt ice caps for water to power your engines) Big Cruch: reset everything for a small multiplier that grows