I might amend and add to this post later...
Some people say that you might want to have several videos displaying your capabilities on various different types of aspects or types of work, however... I'd suggest doing a reel that demonstrates the type of work you're happiest doing.
That all depends if you're aiming for a specific thing, or want to try doing whatever work you can get your hands on. In the beginning, you might want to stick with the types of work you do best. As you do this, it will bring in more work that you are happy and comfortable doing so there's less chance you find a project that might be too challenging for you at the moment.
Challenging and different types of projects will come your way regardless of how specific your reel is. So you'll get a chance to curate those skills anyways. Then when you're more comfortable and have produced a body of work that does justice to your currently lesser developed skills you can add those to your reels as well.