Here you will a collection of links to all sorts of Mario Maker related places. If you feel like something is missing that should be included, send me a message using the form on the Contact page.
Discord
The Mario Maker Discord is probably the biggest community Discord server. This is also the place where a bunch of the races are organized from.
Black Dragon’s Kaizo Mario Maker Wikia
Black Dragon’s Kaizo Mario Maker Wikia page has a huge collection of Mario Maker kaizo tricks, complete with animated gifs as examples.
One Year of Mario Maker (and beyond)
http://mariomaker.phgizmo.com/
Home of Kiavik’s One Year of Mario Maker (1YMM) project, and of course the sequels as well. They also do a bunch more community projects that all consist of a high number of quality levels.
Super Mario Maker subreddit
Super Mario Maker 2 subreddit
The Super Mario Maker pages on Reddit. There’s usually plenty of discussion and level sharing happening there.
They also have a Discord server.
Warp World
If you’ve ever watched a viewer level stream on Twitch, they were probably using Jaku’s Warp World as their automated queue system.
[SMM1] Nintendo’s Super Mario Maker Bookmark Site
On Nintendo’s Super Mario Maker Bookmark site you can easily check out level previews and stats, and even add levels to your in-game bookmarks if you log in with your Nintendo id.
Hopefully one day Nintendo will create a bookmark site for Super Mario Maker 2 as well. Until that time we’re stuck with the in-game system.