In all honesty, the “small events” like The Court of Owls are called story arcs, so they’re not events in the same way that Crisis on Infinite Earths and the like are. They’re regular storylines.
I’ll give this a whirl. I’m not counting things like the JLA/JSA crossovers as those were annual crossovers in Justice League of America, nor will I count franchise specific stories like No Man’s Land. I’m counting the big, branded, linewide events and stories that are close enough to that criteria.
Offhand and without using outside resources, there’s:
-Crisis on Infinite Earths
-War of The Gods
-Eclipso: The Darkness Within
-The Death and Return of Superman (franchise specific by and large, but it did also entail the Justice League America and Green Lantern series, so it isn’t Superman-only)
-The Final Night
-The Millennium Giants (mostly Superman based, but it did also involve Aquaman, Challengers of the Unknown and the Teen Titans)
-Our Worlds at War
-Joker’s Last Laugh
-The Sinestro Corps War (GL specific by and large, but Blue Beetle was included, and as it began, Dan DiDio said it was the 2007 event)
-Justice League vs. Suicide Squad
-Dark Nights: Metal
-Year of the Villain