Many fictional organizations rank their members with Greek letters. Such ranking systems usually progress alphabetically- 'alpha' refers to a leader note or uber-badass, 'beta' refers to their Number Two, and so on.
If the letters denote power level instead of someone's rank in a group, that's Random Power Ranking (although the two tropes often overlap because Asskicking Equals Authority). Compare Gratuitous Greek (which is about how works (or items/technology within a work) involving futuristic science often have a Greek letter in their title) and Alpha and Beta Wolves (when this trope is used for wolves).
- In DARLING in the FRANXX, 'pilots' are referred to by number, and some have letters such as iota attached to their number.
- In Soul Eater, Chrona's various attacks are named with the pattern "Screech [Greek Letter]", from least powerful to most powerful. In this case it emphasizes the cold and clinical conditions they were raised under and the fact that their abilities are experimental; other characters use more traditional attack names.
- In one of the overlapping examples mentioned above, X-Men has Omega-Level Mutants, which are mutants with a power so strong that they are Person of Mass Destruction material. Whenever they are part of an organization, including the titular team, they are wholly acknowledged to be the "big gun" of the group.
- In lost seasons, a Kung Fu Panda fic, a pack's alpha is its strategist and the beta (there's only one beta in any pack) is essentially an armsmaster/field commander. The narrator's pack allied with Shen because they thought he could replace their deceased alpha; without one, a pack disintegrates.
- In the Persona 5/Torg crossover fic The Dance of Dominance, demon groups go by martial strength; the strongest is alpha, the second strongest is beta, and so on. Demons use these terms even if the group they're in is mostly human.
- In Alpha and Omega, the former are a wolf pack's best fighters and hunters, and 'omega' is a catchall term for everyone else. It's an Omega's role to defuse tension within and between packs, so the alphas don't fight unnecessarily. The two types aren't allowed to mate, and omegas don't have much official power, yet every pack onscreen has some.
- In Up, Muntz names his dogs after Greek letters according to their rank. Dug, the Minion with an F in Evil, has an Odd Name Out, which suggests he's so low on the hierarchy that there were no letters left to assign him. When Dug defeats Alpha, the other dogs make him the new Alpha.
- In Edge of Tomorrow, the alien Mimics have three biological castes. The basic foot-soldiers are just called Mimics. The Alphas are the commanders, and are also capable of sending their memories into the past should they die. And the Omega is the supreme leader of the entire Hive Mind, and possesses a time-reset ability similar to the Alphas.
- In Zoe Chant's Paranormal Romance novels, these terms can refer to either rank or a were's nature, which they are instinctively hardwired to follow. Alphas and betas both fight, but only alphas are stubborn enough to risk themselves in dominance fights over pack note leadership; betas are more pragmatic. (It's noted that this isn't a bad thing.) There can only be two alphas in a group, so most alpha shifters are loners.
- In Brave New World, one of the Trope Codifiers, people are all genetically engineered and designed to fit into castes ranging from Alpha (the best and brightest) to Epsilon (simple-minded workers for the simplest jobs). Here the trope overlaps with Random Power Ranking, because the ranking is based on intellectual power.
- In the Alliance/Union series, the clones created by the Union are created and trained in categories designated alpha through epsilon (in an obvious shout-out to Brave New World). The alphas are the smartest clones- the ones most likely to graduate to full citizenship- while the epsilons are slow and stupid and assigned to all the most boring jobs. This only applies to those clones created by the Union government to address its horrible manpower shortage; clones made by private citizens and raised as normal children are outside of the alpha-epsilon system and are always considered full citizens.
- In Patricia Briggs's Alpha and Omega novels, the letters are both titles and ranks (because of Personality Powers). Alphas command. Omegas are peacemakers who must be protected from fights.
- Zigzagged in Breaking Dawn. A (werewolf) pack leader is an 'alpha', but everyone else is titled 'second' or 'third' as befits their place in the hierarchy.
- In the Star Trek: Deep Space Nine episode "One Little Ship", Jem'Hadar are referred to by the quadrant in which they were created. Alphas come from the Alpha Quadrant, for example. Each type has traits meant to make them better warriors against opponents from governments in the corresponding quadrants. (The system is not alphabetical; Gammas were created before Alphas.)
- In Blake's 7 the Federation's social classes are "alphas", "betas", "gammas", and "epsilons".
- Warhammer 40,000:
- The psyker rating scale goes all the way from Alpha Plus (can snap a Titan in half with their mind) to Omega Minus blanks (invisible to daemons and cause immense suffering to psykers just by being present due to their having no Warp presence). Baseline humans are Rho or Pi.
- Particularly tough versions of individual Tyranid strains are referred to as Alphas.
- Some Heartless raid bosses in Kingdom Hearts χ have Palette Swapped variants more powerful than the original. These variants were labelled "Subspecies" in the original game and "Omega" in the English translation.
- When Drunk on the Dark Side, the Soulcalibur V character Pyrrha's name changes to "Pyrrha Omega".
- The Metroid aliens metamorphose through "stages", not unlike butterflies. From weakest to strongest, the stages are: larval, alpha, gamma, zeta, omega, Queen.