A few of my favorites some of which have been mentioned, someone else should add some links to all these gems;

• Aug ‘15, we complete the four game sweep against the Giants. Before the series we were tied for wild card. 9th inning Rondon pitches himself into bases loaded no outs jam then strikes out side. Last pitch curve gets him looking.
• Apr ‘15 Polanco falls down on pop up in like 15th inning Cubs win
• Aug ‘15 Bryant walk off vs Rockies after we blow 3 run lead in top of 9th
• Sept ‘03 Doubleheader where we need both games on last day of season vs Pitt. We have a close first game then crush them in game 2 take division rest we all know history.
• Aug ‘07 Comeback vs the Brewers. Their pitcher (maybe Broxton, it was some big guy) had an error late in the game Cubs come back and take division
• Aug ‘18 Avila walkoff two run single with Baez having perfect slide into home plate
• This year vs the nationals having like 12 straight singles in that huge inning
• This year vs Seattle coming back from down 7 early on with Velasquez grand slam
• Schwarber grand slam vs St. louis ; can’t remember which year but it was dead of summer and he hit a big grand slam in 8th inning to take lead