Well, here are my endings that I came up with. ONE HUNDRED PERCENT VENT/WIZARD KID FREE YA'LL:
"Normal" Ending:
The Crucible successfully attaches to the Citadel. The console activates, Shepard uses it to fire. As the super weapon begins to wind up, Shepard staggers back, easing him/herself down next to Anderson's body. The Cruicible fires. A green shockwave is sent out, permanently shutting off every Reaper in the Sol system. The shockwave is also sent through the Charon relay to every Mass Relay in the Milky Way (NOT destroying/disabling them), effecting every Reaper in the rest of the galaxy. Shepard succumbs to his/her injuries at peace, knowing that the mission had been a success. Memories of his/her Love Interest and crew members fill his/her head, as life leaves his/her body.
Epilogue:
Cutscenes of various races are shown celebrating, rebuilding. A voice over remembering Shepard plays, with various surviving squad members from all 3 games speaking a different line each.
Post credits:
Similar to the actual post credits scene, a human grandfather is telling his young grandson about the galaxy, and about Shepard.
"Bad" Ending:
The Reapers destroy the Crucible before it could attach to Citadel. Shepard and the player watch in horror as it falls to Earth in ruins. A red hologram of Harbinger appears on the console, similar to Sovereign on Virmire. It berates Shepard (e.g. "You were destined to fail. The cycle is infinite, your end was already written") as he/she dies next to Anderson's body, knowing he/she had failed.
Epilogue:
Cutscenes of various races being harvested by the Reapers are shown, with Harbinger continuing to talk over them. Scenes of surviving squad members being killed are also shown.
Post credits:
Tens of thousands of years into the future, an alien race finds Liara's records of our cycle, which include details about the Crucible and Shepard.
"Good" Ending:
Events play out the same as the "Normal" ending, except that Shepard only loses consciousness instead of dying. Keepers appear, and carry Shepard away.
Epilogue:
4 months later, Shepard wakes in a hospital on Earth. Various members of his/her crew are there to welcome him/her back. His/Her Love Interest, or Joker if no Romance occurred, explains what happened in the past 4 months, how he/she got here, etc. The nurse enters and asks everyone to leave, giving Shepard some time alone. A Shepard monologue begins over the cutscene, as he/she watches a family outside his/her window play. Like the "Normal" ending, scenes of various races rebuilding and celebrating are shown. Shepard's monologue could be different depending how Paragon or Renegade you are, and maybe what you did over the 3 games. The final scene before the cut to credits is of the Milky Way.
Post credits:
A scene with your Love Interest (or if you didn't enter a Romance, with Joker) set some time after Shepard is discharged from hospital. Depending on your Love Interest the scene will be different, a different location, discussing some different things, etc. Basically it comes down to Shepard and the person he/she is with discussing their future.