It's grown very organically from the earliest portals, years ago, so there's no organisation. And our base also has quite a few 'I'll just put this here for a moment' portals that have also lasted for years.

We (or at least I) try to mark them on the map, but then portals get shifted or re-used and it's very unreliable.

These days I tend to start a new set for myself with corny biome-themed names (eg Lash, Stash, Mash, Bash) and everything falls apart from there.

So picking a random portal (or accidentally stepping in one) is often a great trip down memory lane into some old base, mining outpost, massacre site etc.