First and foremost, I cannot recommend Pastor Fisk's Worldview Everlasting videos enough. He posts insightful, well researched, relevant videos that are also entertaining enough to make their 15-20 minutes fly by. He posts around two videos a week, which helps feed "your favorite YouTube addiction" quite nicely.
On Greek Tuesdays he walks through one of the Scripture readings for the upcoming Sunday, explaining the translation, appearance, and meaning of a selection of Greek words within the context and with a Lutheran explanation. I especially love these because it gives me some good food for thought to contemplate the rest of the week. And, having recently been walked through the reading, I find myself better prepared to listen to my Pastor read and preach on Sunday morning.
Here's last week's Greek Tuesday on John 20:19-31:
Fridays bring AskdaPastor2.0, as Pastor Fisk responds to questions he receives from viewers about topics like drunkenness, dating, and law & gospel. These are great especially for learning Lutheran theology, often in contrast to other theological views (like double predestination or TULIP) that are really confusing, on topics that don't often fall into the standard Sunday morning Adult Bible Study.
Here's one about TULIP:
And now for something completely different: The other Lutheran addition to my YouTube subscriptions is Pastor Fiene's The Lutheran Satire channel. There are a lot of videos in this style currently: poorly computer-animated figures have awkward conversations with each other. These videos are satirical and often hilarious and he has a few "series," like Things Your Lutheran Pastor Totally Loves, An Honest Conversation, and Super True Stories.
Things Your Lutheran Pastor Totally Loves: Hearing Complaints from "Some People"