Synthaholic on the Vintage Synth Explorer forum offers a link to download about 120 microKorg patches on this post. The download is free and the files are in the microKorg Sound Editor format, so you will need that program to load them.
Todd Smith created a bank of Trance-style sounds for the microKorg. You can download them for free from his Dropbox account here: Todd Smith microKorg Patches. View a demo of these sounds on his YouTube account.
SynthLib offers a handful of user-uploaded microKorg patches of various styles. Each is a free download.
The illustrious Cuckoo created 128 original patches for the microKorg to celebrate the 16th anniversary of its release. The patches are available for $20. About the sound pack, Cuckoo says, "I've made it especially with keyboard players in mind, with the goal of creating truly versatile and useful musical patches." He also produced a wonderfully in-depth video demo of the sounds on YouTube.
Thoracius Appotite offers a bank of about 130 microKorg sounds based on various vintage analog synths. The bank is available for purchase for about $25. There is a preview of the sounds on the website.
Albaecstasy offers 2 banks of microKorg sounds (256 patches total) for sale on their website for €27.
The Synth Patches website offers a bank of 100 patches for fans of Boards of Canada, Tycho, Tame Impala, and more for $12.
You can download the microKorg manual from Korg's website here.