Here an updated list of local comic/science-fiction/anime/etc. conventions in the Colorado area in 2018. In this update, I added one that's this Saturday (two days away)!
NOTE: This does not include gaming conventions. I thought about adding them, but decided against it, just because I'm unlikely to ever go.
WPL Mini-Con 2018September 8
Gunbarrel Pop-Up Comic Con
October 6
Pikes Peak Comic Convention
October 6
MileHighCon 50
October 19-21
Chey-Fy Comic Expo
October 26-28
DakuCon
November 9-11
Rocky Mountain Con
November 10-11
ChromicCon
November 10
Denver Retro Con
November 18
And here's a cosplay photo -- Rose Quartz (from Steven Universe) by the pregnant-for-real Sarah Cosmama at Denver Comic Con 2018:

Tomorrow's wallpaper
Recent cover scans I added to GCD:
Adventure Time with Fionna & Cake
Disney Tim Burton's the Nightmare before Christmas Manga
Disney Tim Burton's the Nightmare before Christmas: The Story of the Movie in Comics
Donald Trump in "Why Does It Always Rain on Me?"
Incredibles 2: Crisis in Mid-Life! & Other Stories #2 variant