I mostly play "Ascend to godhood" type packs in which the goal is to become basically omnipotent. I remember in one of them after months of play I finally made a Creative Vending Upgrade for a drawer - that's the end, you're basically god now, any drawer which could have a thing in it, can now have an unlimited amount of that thing [yes of course that includes Creative Vending Upgrades themselves]. And yeah, after ten minutes that's pretty boring, a nether star and an oak plank are now the same, but it's also the end of the game anyway so what do you expect.

There are fun twists on this idea, I am currently re-playing Star Factory in which you start with infinite supplies of four ingredients and even the ability to make clones of those infinite supplies. The goal of course is converting those four (marble, gold, dark oak, ice) into everything you need and it's important to automate everything, don't make 64 sand, make a machine which makes 1 sand per second and leave it running forever. Don't make 64 glass from the sand, make another machine which makes sand but this time feed it into a furnace and fuel the furnace with infinite oak wood, now you've got unlimited glass. And so on.