Have I mentioned that I'm a Mycroftian more than a little?
If you start with thecutteralicia, you can't go wrong. Try the Mycroft Meta series. Here's a few to tantalize you with:
The Holmes brothers, or why Mycroft is actually Sherlock's parent...
Mycroft and John (and addiction)
the man behind mycroft
the morgue scene: an analysis
Mystrade fic Puppet on a String (in Fire and Ice series). Not persuaded into shipping per se, sorry; but this particular fic is so good, oh my. I highly recommend it. Found through thecutteralicia. Bless!
I have never read any other writer's Mystrade, nor am I likely to, barring the sequel by the writer of Puppet. It's called Waste Land and has only one chapter at present. If you read Puppet, you'll want WL right after, trust me.
Another Mycroftian is seeking some pre-canon Mycroft fics. Can folks send her whatever you've found, please? I'd especially love for one of you to please send her the Holmes Boys stories from SherlockCares.
-- No, I do not have a tumblr account, and no, I am not getting one this week. Probably not this year. Have you SEEN how much I blog here??? Have some pity. ;b