Here's my list
1) That Locke was the thing inside Allana's cargo box and the "resurrected" Locke was Jacob's nemesis 2) Michael killing Ana Lucia and Libby 3) Through the Looking Glass was a flash forward 4) Locke is Jeremey Bentham 5) The man (Desmond) is what was inside the hatch 6) Desmond crashed Oceanic 815 7) Anthony Cooper is the original Sawyer 8) "Jacob" wants Locke to move the island 9) Ben kills Locke/ Jermey Bentham 10) The neighborhood Juliet is in is on the island and is where the others live 11) Ben's spy is Michael 12) The boat belongs to Charles Widmore 13) The Constant is not a flashback, but rather Desmond time-traveling 14) The woman (Ms. Hawkings) knows all about Desmond 15) Sayid shoots young Ben 16) Penny is the one to rescue the Oceanic 6 17) Juliet survives falling through the swan and detonates jughead 18) Penny's arctic team "thinks they found it" 19) Christian is Claire's dad 20) Locke was "resurrected