Here is an Alien timeline consisting of the events of Alien, Aliens, Alien 3, Alien: Resurrection, Alien vs Predator, Aliens vs Predator: Requiem, Prometheus, and Alien: Covenant. The games, books, and graphic novel events are not included in this Alien timeline. This is a simple timeline, mostly taking into account the most important events from the movie or events referenced in the Alien movies.
Alien vs. Predator: 2004
1904: The inhabitants of Razorback Point Whaling Station are caught between a fight between Aliens and Predators and are killed.
2004, October: Charles Bishop Weyland leads a team to Bouvet Island in Antarctica to investigate an energy surge created near the abandoned whaling station. They discover and enter an ancient pyramid underneath the ice, which is used as a training ground for Young Blood Predators. Three Young Blood Predators also enter the pyramid, and a clash between humans, Predators, and Xenomorphs breaks out. Only Alexa Woods, Scar Predator, and the Alien Queen reach the surface, while the temple is destroyed with a Yautja self-destruct device. Alexa Woods is blooded by Scar Predator, who is killed shortly after by the Alien Queen, who drops under the Antarctic ocean. The body of Scar Predator is taken away by his clan, carrying a Predalien embryo.
Aliens vs. Predator: Requiem: 2004, October
2004, middle of October: A Predalien erupts from the body of Scar Predator and causes a Predator scout ship to crash near the town of Gunnison, Colorado.
A Xenomorph outbreak occurs in and around the town while Wolf Predator is dispatched from Yautja Prime to clean it out.
While having initial success at destroying the scout ship, Wolf is soon overwhelmed by a large number of Xenomorphs and the Predalien in the town.
A final fight between Wolf and the Predalien erupts on a hospital roof, while the US forces nuke the entire town.
A small group of survivors escape in a helicopter, carrying a piece of Predator technology.
2004, late October: Wolf Predator's' plasma pistol reaches the hands of Miss Yutani, presumably from the Yutani Corporation.
2089: Dr. Elizabeth Shaw and Charlie Holloway discover a star map on Earth that points to LV-223.
2091: The Prometheus mission leaves Earth.
2093: The USCSS Prometheus reaches LV-223 and finds an abandoned Engineer bioweapons facility. The facility is investigated but most of the crew are killed as a result of the Black Goo Pathogen, a highly mutagenic substance found in black jars. Sir Peter Weyland is revealed to be on the ship but is killed by a surviving Engineer who is awakened from stasis. The USCSS Prometheus is destroyed by crashing it into an Engineer Juggernaut that is about to take off for Earth with a pathogen payload.
2094, January: Dr. Elizabeth Shaw leaves LV-223 on another Juggernaut ship. A Deacon is born from the body of the unconscious Engineer. There is nobody else left alive on the planet at this point.
Alien: Covenant: 2093
2094, late January: Dr. Elizabeth Shaw repairs the broken remains of David. They set the course for the Engineer Homeworld and Shaw goes to hypersleep.
2094: The Juggernaut arrives at Planet 4, David wipes out the Engineer population of the Engineer City. Dr. Elizabeth Shaw is killed due to unknown reasons.
2103: The Covenant mission leaves Earth with the purpose of reaching the planet Origae-6 to colonize it.
2104: The Covenant mission receives a transmission from Dr. Elizabeth Shaw and lands on the Paradise planet to investigate. Most of the awakened crew of the USCSS Covenant are killed by Neomorphs, Protomorphs, or David, except for Katherine Daniels and Tennessee Faris. David takes over the USCSS Covenant while assuming the role of Walter and the ship returns back to its course for Origae-6.
2112: The estimated arrival time of the USCSS Covenant at Origae-6.
2121: The Nostromo leaves Thedus on a course to Earth with a crew of 7: Kane, Dallas, Lambert, Ripley, Ash, Parker, and Brett.
Ash is added to the crew at the last minute.
2122: Nostromo lands on LV-426 to investigate a derelict transmission, they find a derelict ship where executive officer Kane is impregnated by a Facehugger. Kane is brought onboard with the Xenomorph chestburster, which emerges, grows rapidly, and wipes out most of the crew in 24 hours. Ash is revealed to be an android which malfunctions and is destroyed. The Nostromo is destroyed by a self-destruct, the only survivor Ellen Ripley escapes in the Narcissus shuttle. Ellen Ripley sets the shuttle on a course to the Core Worlds and goes to hypersleep together with Jones the cat.
2120-ties - 2170-ties: Gateway station is built orbiting Earth.
2150-ties: The Hadley's Hope colony is established on LV-426.
2179: The Narcissus with Ellen Ripley is picked up by a deep space salvage team.
2179, June 12th: Carter Burke sends a transmission to Hadley’s Hope to locate the Derelict.
2179, June: The Jorden family finds the ship and investigates, Ross Jorden is first to be impregnated.
2179, June - July: Hadley's Hope with the population of 158 is infested by Xenomorphs.
2179, July: Contact with Hadley’s Hope colony on LV-426 is lost.
2179, July: A USCM team led by Lieutenant S. Gorman is sent to LV-426 to investigate a contact breakoff with Hadley’s Hope in the USS Sulaco. Ellen Ripley is sent with them as a consultant. The marines find only 1 survivor, Rebecca Jorden. Most of the marines are wiped out by Xenomorphs or friendly fire, Atmosphere processor goes critical, the colony and surrounding area destroyed. The mission has 4 survivors: Ellen Ripley, Dwayne Hicks, Bishop 341-B android, and Rebecca Jorden.
Alien 3: 2179, August
2179, August: The USS Sulaco jettisons the survivors of the LV-426 mission in an EEV as a fire is started on the ship by a Xenomorph.
Ellen Ripley is impregnated.
The EEV crash lands on Fury 161, a prison planet with 23 prisoners, 2 wardens and a medical officer.
Dwayne Hicks and Rebecca Jorden are killed in the crash. A Xenomorph is brought along in the EEV, it infests a dog/ox, kills most of the prisoners, Warden Andrews and medical officer Clemens.
Ripley consults heavily damaged Bishop and shuts him down. The Bishop II android with a team of special forces is sent to acquire Lieutenant Ripley on The USS Patna to get ahold of the alien queen specimen inside her.
Ellen Ripley commits suicide, warden Aaron is killed. The only survivor is prisoner Morse. Fury 161 is closed down.
Alien: Resurrection: 2181
2381: Ellen Ripley is cloned on the USM Auriga after 7 unsuccessful attempts, she is named Ripley 8. An Alien Queen chestburster is taken out of her, and Ripley recovers inhumanly fast from the surgery. Commercial Freighter Betty docks with the Auriga, and a team of mercenaries delivers a dozen human hosts for the Auriga scientists. The aliens break out, most of the Auriga crew is killed/captured in 1-2 hours, and some manage to evacuate. Ripley joins the Betty crew and manages to escape from the ship, half of the Betty crew is killed. The USM Auriga crashes to Earth. The Betty lands on Earth with Ripley 8, Call, Johner, and Vriess.
The Alien timeline is something created back in 2002 and dusted off from the old site to update with the information from then new movies and correct any errors. If you are interested in Predators, check out the Predator timeline, which also includes information from the comic books.