User:Trekhistorian

My personal list starts with the Urhumanids:

1. ca. 4 Bio. years ago

Imotru aka Urhumanoids (TNG)

2. ca. 3,5 Bio. years ago

Time-Travel: Q and Picard (TNG)

3. ca. 250 Mio. BC

Preservers (a novelle)

4. June 64 018 143 BC

Time-travel: Kirk, Spock, McCoy, Reenie, Vernon, Bannon, Emmendorf, 2 klingons and the Clan Ru landing party (a TOS novelle)

5. June 64 018 143 BC

Q's Asteroid (a Q-novelle)

6.  June 64 018 143 BC

Preservers save Hadrosaurs (the ancestors of the Voth) and Troodonts (the ancestors of the Clan Ru) (VOY and a TOS novelle)

7. ca. 11 Mio. BC

The cetacean probe (Star Trek IV)

8. ca. 200 000 years ago

Questor androids

9. ca. 42 600 BC

the "Spirits of the sky" (VOY)

10. ca. 14 000 BC ?

Q, Spock, McCoy, Chekov - (Star Trek/Legion of Super-Heroes)

11. 12 735 BC

Danons (see memory beta)

12. ca. 10 000 BC

Preservers save some Indians (which are later seen in the TOS episode "The obelisk" Miramanee etc.)

13. 7631 BC

Nommo from Sirius by the Dogon people in West Africa (DS9)

14. 4032 BC

AEGIS (TOS, some comics and novelles)

15. 4032 BC

Counterstrike (TOS, some comics and novelles)

16. 4003 BC

"The One" aka the monotheist god (Star Trek V and some TNG Q-novelles)

17. 4004 BC

Ardra (TNG)

18. ca. 4000 BC

Djinn (Comics)

19. ca. 4000 BC

Okari-Anunnaki (VOY novelles)

20. ca. 3500 - 3400 BC

Aliens from Zeta Reticula II in ancient egypt (TOS Marvel Comic 13)

21. ca. 3000 BC

Kukulkan/Quetzalcoatl in ancient egypt, later in ancient China and Mesoamerica (TAS)

22. ca. 3000 BC

Felisians (see memory beta)

23. ca. 2738 BC

Greek gods ( Who Mourns For Adonais? ) (TOS)

24. ca. 2700 BC

Furies

25. ca. 2560 BC

time travelling historian from the 29th century at the Chops pyramide in Gizeh seen in an Enterprise episode

26. 2240 BC

Megans, Satyrn (TAS)

27. ???? BC

Elves, Selelvians (novelle)

28. ca. 1350 BC

Ay and Patricia Graves in ancient egypt (memory beta)

Of coure, there are a lot of others, like the Sahndarans in Platons Stephildren and so on