Before I start, I'm assuming your league is fairly similar to most others I've been in which are roughly:
1 point per tackle
3 points per sack
3 points per INT
7 points per defensive TD
The first thing I want to put out there is that if they are close to this scale, the bigger tacklers are the best scorers and the most consistent from week to week.
If we do the math, a guy with 100 tackles and 1 INT and 1 sack would score 106 fantasy points over the course of a season whereas a guy with 40 tackles and 15 sacks would score 85 points and a guy with 50 tackles and 8 INTs would score 74 points.
Top tackling linebackers are always the best bets for IDP leagues just for the mere fact you can count on them for 5-9 tackles almost every game.
That being said, I'll get to the individual rankings in a little bit. I want to take some time to finish the QB rankings before I get too sidetracked. If you are drafting immediately, take a look at the top tacklers from last season and you should have a good basis for who to look at in IDP leagues.