Good news! There is no limit on the number of apps that you can have in your Fulcrum plan. We have quite a few users that have 100s of apps, so feel free to make as many as you want.
If you do have a lot of apps, you may want to make use of the app status feature. Setting an app status to inactive when it is not being used will prevent it from being downloaded to the mobile apps. This will help to reduce sync times when first logging in on the mobile app.