Last thread: >>1804813
Current best sites to find videos:
Sita's site: trollvids.com Mostly English MMD, feedback always welcomed.
Nicovideo: Search MMD, mikumikudance, R-18, 紳士の社交場.
Video.fc2: This is a sinking ship, save what you can salvage.
Vimeo: Grab them before they're gone.

List of free apps/addons (google them) that might help you with downloading vids:
NicoFox
Downloadhelper
Freemake Video Downloader
JDownloader 2 beta

IRC /e/roMMD chatroom
Mostly idling so you might want to leave the tab open and wait for an answer.
#erommd at rizon

For individual models and motions downloads
http://trollvids.com/resources.html

If you need any help, just ask.