Language Drift: Sort-of averted for Eldraeic, due in equal parts to its origins as a designed language intended to communicate precisionist-grade thought and to its ongoing tending by the logotects, et. al., of the Conclave of Linguistics and Ontology, who are prescriptivists nonpareil. Only sort of, however, since their department of Worthy Innovations routinely combs the language as it is spoken for, well, worthy innovations to be taken up into the canonical version.
Since they’ve been doing this for a long time, and since almost nothing can ever be thrown out due to the obvious need for backwards compatibility in language design, the result tends to be — well, if it were English, they’d be like this (courtesy of xkcd):
Played rather straighter by most other languages of the Worlds, although both the influence of Eldraeic via Trade and that of the pervasive communication networks of starfaring cultures do tend to slow it down a bit.
Killed to Uphold the Masquerade: Again, a tactic used primarily by lower-tech and lower-ethics organizations, ones which can’t manage or don’t bother with amnesic drugs, memory redaction, a geas, simple memetic discrediting, or if all else fails, a trip to a perfectly nice, perfectly comfortable luxury space resort that no-one ever leaves.
Kill It With Water: Leaving aside such not-really-the-water examples as water knives, pressure effects, and drowning, this is rather rare, inasmuch as the universe is full of the bloody stuff and as such having much of a vulnerability to water is unlikely to let you live long enough for anyone to actually try to kill you. (And any species having one would be unlikely to be so freakin’ stupid as to invade a small sylithotectonic world whose surface is something like three-quarters covered in the stuff. Yes, I’m looking at you.)
Perhaps the best known related, not-really-the-water-but-more-so-than-some, example exists mostly because of those species whose native temperature range is such that water’s natural state, as ice, is a kind of rock. And being hit by a stream of liquid water, therefore, is much like immersion in lava.
Kill and Replace: A tactic – and with modern sophotechnology, a lamentably obvious tactic – used by lower-tech and lower-ethics intelligence agencies, for whom fast-growth cloning (or even radical plastic surgery) and programming is the best they can manage – rather than the implantation of overshadowing gnostic overlays used by the technological sophisticates among shady organizations.
Jump Jet Pack: A ubiquitous addition to virtually all combat armor (see: light infantry), scout armor, and the equipage of just about everyone else who can benefit from high mobility, from disaster relief teams to microgravity construction workers.
(Being able to bend momentum with your mind is nice, but some rocket thrusters sure help.)
In The Future, We Still Have Roombas: There are probably something like 10,000 of these little guys – from literal space-Roombas to the more general purpose utility spider and cogsworth– running about (or fixed in place) performing various mundane tasks for every robot that we might recognize as something like your typical SFnal robot.
Intangibility: Has yet to be successfully developed, for most of the reasons given in the trope page (although I disagree on one major point: intangible objects can and probably should have mass; it’s the electromagnetic interaction they need to be lack in order to properly interpenetrate).
There is one prominent failure mode, however: muon metals, thanks to the Pauli Exclusion Principle, can pass through normal (electron-ic) matter as if it wasn’t even there, since electrons and muons do not mutually exclude. This makes life interesting if the magnetic couple necessary to hold the (muonic, due to the spectacular refractory properties of muon matter) magnetic nozzle of your torch drive in place fails, since you may well see said nozzle fly right through the rest of your ship and indeed you, impelled by the remaining coupled thrust. People tend to find this disturbing.
(Well, briefly, since a mere moment thereafter they tend to be preoccupied with the stern of their starship melting, vaporizing, and exploding, due to the ensuing catastrophic drive containment failure. And yet.)