Grand Reality
Grand Reality encompasses everything that was, is, and will be. If it can be imagined, it exists within Grand Reality at some point in time. Essentially, Grand Reality is what you might call the Multiverse, and indeed some do call it that. It has a beginning, but no end. So even though spatially, it is never infinite at any one moment, it is infinite in the sense that its time is infinite.
One thing to note is that you reading this do not exist in this place, even if an exact copy of your universe exists somewhere in Grand Reality, since it contains all that can be imagined. Though, once that universe is tainted by some evil, yours will thankfully be completely fine.
So that is the simple outline of Grand Reality.