Take esseli starships, for example. Unlike the link!n-Rechesh (who would be another fine example), they know better than to try to grow fully organic starships, so from outside the hulls and drives look relatively normal. Then you go through the airlock, and it’s all flesh, all the time, with heart-valve doors, neuron-cluster control interfaces, food-secreting glands, recycling intestines, and suspicious organic gurgles everywhere. Mining ships have refinery stomachs and tentacles.
Múrast starships are carved out of ice bodies, with the necessary technology fitted within, and then refrozen. Which is all very sensible when you consider their favored environment, but doesn’t explain why they always carve them into baroque cathedral-like structures rather than anything more utilitarian.
And then there are the seb!nt!at, who as creatures of nuclear forces that dwell deep within stars, do not build their starships out of matter in any conventional sense.
Starfish Aliens build Starfish Starships, basically, just as far as physics will allow.
The tortured structures built by rogue mining drones and other wild mechanicals are about as Gigeresque as it gets, though.
Starfish Aliens: Most of them. Digisapiences, of course, have no bodies at all. The galari are sophont crystal-virus hybrids with inbuilt techlepathy and mechanical psychokinesis. The codramaju are pseudo-fungoids which can merge, exchange, and separate bodies and minds at will. The kaeth are vaguely draconic pseudosaurians with a metal-rich biology. The hydrogen-breathing sssc!haaaouú are fragile collections of membranes that dwell in the upper layers of gas giants. The myneni are crystal-based carbohydrosilicate amoeboids with built-in chemosynthetic talents. The mezuar are a network of collectively sophont purplish-blue trees. (Yes, as sessile as that implies, although the selyéva are green-blue plantimals – non-sessile photosynthetics – who probably most closely resemble walking broccoli.) The esseli have engineered themselves into brains with manipulating tentacles and customized personal auxiliary organs, and don’t even remember what they used to look like. (And the link!n-Rechesh are heading that way.) The qucequql are ammonia-metabolising octopi from a world of nitrogenous oceans. The múrast would be simple multiheaded snakes, except that they breathe methane, live in oceans of hydrocarbons, and their primary body structures are constructed of ice. The ulakha are metal-plated, fast-moving lizardoids who think Venerian conditions are just about right for a planet. The linobir resemble furless, leathery-skinned, hexapedal, hermaphrodite bears. The shan kari resemble larger versions of Terran mustelids fairly closely, actually, except they prefer to breathe warm methane. The mirilasté are legged-serpents with skin we would recognize as essentially plastic, who breathe the most astonishingly noxious fluorine-hydrocarbon soup. The ktelaki are furry arachnids with trilateral symmetry and multi-branched legs. The seb!nt!at are star-dwelling creatures of plasma and electromagnetic force. The celsesh are quadrilaterally-symmetric with a fused-barrel body plan, and sensory organs on stalks in lieu of a head. The embatil are worm/tentacle creatures whose life cycle begins with individuals, but which merge into single creatures as they mature – while transforming a ganglionic into a collegiate intelligence. The tennoa are chlorine-breathing radial-crabs blessed/cursed with obligate utilitarianism…
And that’s all before we get to uplifts, neogens, and exotic neomorphic bioshells.