Mohs Scale of Science Fiction Hardness/World of Phlebotinum
World Of Phlebotinum: The universe is full of Applied Phlebotinum with more to be found behind every star, but the Phlebotinum is dealt with in a fairly consistent fashion despite its lack of correspondence with reality and, in-world, is considered to lie within the realm of scientific inquiry.
- The Lensman novels: A classic pulp SF series, which originated the trope of Space Police armed with incredibly powerful and flexible weapons, and arguably, the whole Space Opera genre. Lensmen had intertialess drives, habitable gas giants (with surfaces you could land on)... it was pretty soft even when the first stories were published (in the 1930s), and since then, the Science Marches Onmarch of science has made hash out of most of its assumptions. However, it is remarkably self-consistent, and it did pay respect to basic scientific principles - the FTL drive only suspended inertia, which returned when the drive was turned off. Space combat takes place in 3D. Rayguns didn't cause objects (or people) to magically vanish, but simply delivered enough energy to melt or boil them.
- Neon Genesis Evangelion: A lot of the Applied Phlebotinum in this series involves branches of biology and engineering that neither exist in real life nor are ever likely to exist. "Metaphysical biology," for example -- Doctor Kozo Fuyutsuki's specialty -- is kind of like genetics, only it involves human souls instead of genes.
- Farscape: Rubber Forehead Aliens and even Human Aliens abound, and space travel seems to suffer from a case of Sci-Fi Writers Have No Sense of Scale. Artificial Gravity is so ubiquitous as to not merit mention, and its seems that All Planets Are Earthlike. Time Travel occurs more than once.
- Star Trek: The Original Series: To be fair, many aspects of the show were pretty hard sci-fi when it was created, and only seem strange now after decades of science. Though the setting is stranger than other Star Trek shows, the ships and the technology are much more grounded. That said, it features many softer elements, some of which (e.g. Rubber Forehead Aliens, All Planets Are Earthlike, Aliens Speaking English, transporters) can be explained by the technical and budget limitations of the show when it was made (the 1960s), and others (Time Travel, Disintegrator Ray for example) ... not.
- StarCraft: A borderline case of this category. While it's certainly not as soft as Lensman Or Neon Genesis Evangelion, there are a number of scientifically questionable elements throughout, particularly found in the nonhuman races. On the other hand, most Terran technology seems, if not realistic, than plausible, save for a few elements such as gravity manipulation. Then there's the Psychic Powers, which have no justification at all, but that's to be expected, considering they're a stand in for magic.
- The Star Wars Expanded Universe is marginally harder than the films, and probably belongs in this category. The technology may fly in the face of real-world science, but at least it's consistent.
- A Miracle of Science is just about at the hardest end of this category -- the the Martian Hive Mind and the Mad Scientists contribute a lot of properly implausible tech (although the Decoherence Cannon was apparently a mundane research project), but between these we have things like gravitational slingshots and laser microphones which are ordinary modern technology.