This is the best website for sharing (and stealing) teaching materials for ESL especially in Korea, but really anywhere.
I joined when I moved to elementary school in 2012, and in those early days really depended on it, since the number of preps I had to do was so much greater than at the high school.
These days, I upload rather than download, and have shared around 350 lesson ideas or materials (like PPTs), which have been downloaded by others something like 400,000 times in all. Today I made post #1000 to the forum and received my "Hero of Waygookistan" badge.
No, it's not a big deal, but I haven't posted a single thing all month.