There are three types of closed guards I will play: Double Under Hooks, Reverse Kimura or Russian 2-on-1, and the Over Hook Guard.
I like the Over Hook, because it removes your opponent’s capability to effectively strike, gives you solid striking options, opens up a bunch of submissions, and it is very easy to setup.
One of the obvious attacks from here is the Triangle Choke. What is not as obvious is that you can pin them with your triangle and put them in double trouble. Even if you aren’t a good triangle guy (looking at myself), you can make this work easily for you.