You should leverage angel.co to help you target who to go after.

None... You should make them find you and than your closing chances are much higher.
Post valuable content, work on media coverage or join a high visibility accelerator and send the world the message you are the next big app.
Good luck.

I agree with @Yoash Dvir.

If your app isn't even launched, you not only have a tough climb to get a VC interested ... but any terms you'd be offered would be likely more aggressive than you should want to pursue.

If your app concept genuinely has legs, then simply launch it.

If you're short on funding to accomplish that, pursue angel investments and loans (debt financing) and alternate solutions to close that gap.

Then with a live version ready, push content marketing and PR.

This will grow the app's userbase and the exposure.

The PR need not be "front page" of VentureBeat.

Dig up case studies on "how we got our first X app downloads" (use variations of that). That will give you direction on how to build up a userbase.

That's a much more strategic next step.