I tried to look up the meaning of the names of the agents to understand why they are called so:

1. Yoru: In Japanese, it means "to approach" or to "come near". It is apt for Yoru's play style and transporting abilities.

2. Reyna: With Spanish origins, Reyna is a variant of "Raina", and translates to "Queen". This is significant of how her ultimate is called "Empress" depiction her ultimate skill set like the queen in chess (opinion).

3. Sage: Sage (Salvia) is a spice which is also used to improve health in traditional medicine. For ages, sage has been used for its medicinal properties to protect and heal against diseases. Thus, a perfect name for our healer. Also, sage is green in color which is also the theme of the agent as we see it.

4. Phoenix: In Greek mythology, Phoenix is a bird associated with the sun which regenerated itself after dying. These two elements also form the core ability of the agent - its ultimate to be alive again and fire based skills.

5. Sova: With Slovenian origins, Sova is a nickname for an "owl". Owls can see better than most creatures at night thus making them excellent hunters. The agent has an owl by its side, uses its abilities to see its preys when others cannot and has the catchphrase "I am the Hunter!". Pretty neat.

6. Raze: As a verb, "to raze" something refers to destroying it to the ground. It is an apt fit for our bomb laden agent especially with the rocket launcher!

7. Killjoy: The term, being a synonym to a party-pooper, means refers to a person who does not like other people enjoying themselves. This is mostly applies to the play style that kill joy has as with its turret and ultimate, it does become very annoying for the opponents.

8. Viper: This one is pretty straightforward. "Viper" is a green colored snake and thus the theme of the agent revolves around poison and sneaky game play.

9. Astra: This one's a little interesting. Astra is the plural form of the Latin word astrum meaning "star". However, "Astra" is also a Sanskrit word meaning "weapon". This is very accurate for the agent as it utilizes "stars" as her "weapon".

10. Brimstone: Another double entendre, Brimstone is a bright yellow colored moth - referring to its color theme as well as blinding abilities. It is also the name of a missile of the Britain's Royal Airforce. Thus, the ultimate is called "Orbital Strike" which, in Star Wars, was a military strategy, where huge star cruisers ) would fire their main cannons to the surface of a planet, causing heavy damage to the enemy.

11. Cypher: A "cypher" (also "Cipher") is a message written in a secret code. Further, In cryptography, a cipher (or cypher) is an algorithm for performing encryption or decryption—a series of well-defined steps that can be followed as a procedure. The name, in my opinion, does fit with the whole computer and tech-y vibe of the agent, but I could not find anything very specific.

12. Breach: The term refers to "a gap in a wall, barrier, or defense, especially one made by an attacking army". Being an initiator, Breach is designed to weaken the defenses of the opposite team.

13. Jett: My best guess is that Jett refers to "jet" (aircraft) and its speed representing its skillset which is all about speed. And since wind represents speed, it is found as an important part of her theme.

14. Omen: The term refers to an event regarded as a portent of good or evil. Usually it is used in the context of ghosts as a "bad omen". Since the agent is a ghost, its probably why it has been named such.

I tried but couldn't really find anything relevant for Skye. Do comment if you know what it might signify!

I hope you all find this interesting! Good day!