Anyone found any system that's particularly suited for base building? Are there any quests associated with outposts at all?
Quests? None as far as I know, then again I am fucking around rather than advancing the main quest for 3 days straight ever since I did "Empty Nest". I guess your reward is autism and maybe less walking to shops for raw minerals (although considering how much time I spent looking for prime spots...). Well ok, I think you can auto refuel and jump further if an outpost with He-3 is along the path (loading screen says so? or I saw it mentioned somewhere).
As for systems, well there's so much stuff to mine that it really depends which resources you want to prioritize besides the basic Aluminum, Iron and He-3 everyone gets first (they get used the most either for contruction or for power/interstellar logistics in he-3's case), in how many different outposts and finally if you are willing to autistically try to find a spot where biomes change to get 4+ different resources in one outpost (resources are tied to biomes and spawn evern outside their area shown on the global map if the biome is the same, but maybe less frequently and it takes a lot of tries with landing spots and walking to find the biome change boundary).
Most of the planetary systems containing a planet or moon with indigenous animal life will have the basic stuff needed to start colonizing: Aluminum, Iron, Helium-3 and (I guess, it's useful to have) Beryllium (mostly for solar panels, which you need at least to make sure the source of He-3 for generators delivers it to them and gets you more power). Even the starting lvl1 systems like Alpha Centauri have a few decent picks for mining outposts to start out.
After that Nickel, Copper, Tungsten and Titanium are the most useful. Also farming sealant (rubber-analogue? resin?) in greenhouses is a good idea, that gets used a lot but that requires plant scanning. It's up to you what combination you pick. I have to admit that by dumping so much choice on the player they really made sure that even if people do go for one of the "optimal" popular starting choices like
Andaphron in Navion for Aluminum and Iron.
Cuiously enough water is actually quite pointless to look for because it seems you cannot farm crap in domes outside of it's native body (and need the plants scanned to 100%, and just some are cultivable), and life-bearing worlds always have atmospheric moisture anyway (so you can plane an outpost anywhere and windtrap it, regardless of biome) so there's not need to ship it unless you like cooking or maybe want to mass produce something that takes water as an input in the fabricator.
I personally have 2 outposts in Tau Ceiti for
Aluminum, Berylium, He-3, Iron, Water and Tantalum and 2 planets for some organic materials cosmetics and something else (could have gotten more if I bothered looking for biome boundries) and two in Eta Cassiopeia (gaming the biome change to get
Nickel, Copper, Cobalt, Tungsten, Uranium, Sealant from a greenhouse and maybe something else I forgot, but all the walking and multiple landings gave me PTSD). The latter has one particularly has a hellish location with very annoying predators especially those
stalkers that look like giant headcrab ripoffs which take a shitload of bullets to die.
tl;dr Almost any system that has more than 3 bodies had the basics like aluminum, iron, helium-3 and some life-bearing body for greenhouses you can produce with 2 outposts maximum and no autistic looking for biome boundry landing locations. It's just up to you what combo of secondary resources you want, you'll anyway need to buy the rest as shit comes up as even storage containers for gas/liquid/rocks/manufactured goods use slightly different elements.