| Operator | List | Alternates | Welfares | Limited | Trivia |
| “ | There are no bad Operators, only bad Doctors. | ” |
- The Arknights Fandom Wiki used to have a "tier list" of Operators, which was removed in July 2021 since it is infeasible, if not outright pointless because Arknights require more tactical and strategic execution rather than relying on raw statistics alone, and Operators regarded as weak or underperforming by Arknights tier lists do have their uses.
- All alternate Operators are named after their original, but with a unique epithet associated with the original Operator to distinguish them. The Arknights Fandom Wiki will use the epithet only when referring to the alter if the original is also specifically mentioned.
- Originally alters were intended to use a unique codename, but this was scrapped to prevent them from being confused with the original. This can be seen from Lava the Purgatory being originally named Purgatory prior to the release of Under Tides on the CN server (the Global server retroactively renamed her when Who is Real is released).
- The term "Alter", the most popular denomination for alternate operators, is a carryover from Fate/Grand Order and the Fate series in general. However, for many reasons, this is technically a misnomer:
- While Fate possesses many alternate versions of the same character, only a few of them are actually Alters.
- Alters in the Fate franchise are corrupted versions of certain characters, often not even of a different class, as, the primogenitor of the term, Saber Alter (Artoria Pendragon) and the original iteration of the character are both Sabers.
- By this virtue, only Skadi the Corrupting Heart effectively fits into the Alter paradigm, effectively being an alternate future version of Skadi having fallen to the corruption of her Seaborn blood.
- While the original Saber "Alter" does indeed stand for alternate, new additions seem to suggest these are altered versions instead.
- Due to the specifics of the Fate universe, Alter characters are still technically distinct separate versions of a same person that can co-exist, while all alternate operators in Arknights are all the same person at different points in time.
- While Skadi the Corrupting Heart is the only alternate operator that comes from an alternate future which has not happened, and seems to not be canonical as of the ending of Under Tides, she nevertheless remains a possible future of the same person as Skadi.
- Most operators designated as "welfare Operators" notably have a higher DP cost (excluding Potentials) than comparable Operators of the same rarity and subclass as them, costing 2 more DP than them. To compensate for this, most welfare Operators typically have three Deployment Point reductions from their Potential upgrades instead of the usual two DP reductions that all other Operators have.
- After The Wheat and the Anthem headhunting banner, the number of new 4★ Operators introduced to the game have significantly declined ever since; with exceptions to collaboration/crossover events and Shop Vouchers Store, all 4★ Operators after that point are introduced only in headhunting banners debuting alongside a new Main Theme episode.
- In the beta version of Arknights, all Operators' rarity were decreased by one as there were no 1★ Robots. For example, Exusiai would be a 5★ instead of the current 6★.
- Interestingly, a majority of the male 6★ Operators released thus far notably have an unusual trend of being heavily skewed towards being classed predominantly as Guards or Specialists, whereas all of the male Operators of a 5★ rarity or lower and female Operators are far more varied in regards to Operator class.
- The only few examples of male 6★ Operators who do not follow the above trend are operators such as Gnosis, Lumen, and Vigil, whom have the distinction of being the first male 6★ Operators who are classed as a Supporter, Medic, and Vanguard, respectively. There are currently no male 6★ Operators classed as a Sniper or Defender.