Recently I acheived the 'Completionist' badge when I marked my 113th drama as completed. This is an arbritary number and very much don't believe other people achieved this badge at his exact point. I had marked so many dramas as 'dropped' right before achieving this badge, so it didn't have anything to do with 'completing a lot of dramas in a row'.
Gift Giver badge I didn't note but I am guessing its from sending 25 gift awards
Thoughtful badge I think was 50 gift awards, and
Generous was from sending 100 gift awards.
I've personallly been after the 'bouquet sender' badge for 1 year with some people having sent 30k flowers having it and those sending 35k flowers not having it. I will update this post once I get the badge to provide people with an indicate number.
Daily Dynamo I still haven't received even after logging in every day for a month. Don't know how long that badge will take.