Custom Object Limitation

This limit represents the amount of Custom Objects permitted to an organization based on their edition.

The default values are:

Contact Manager: 5
Group: 50
Professional: 50
Enterprise: 200
Unlimited and Performance: 2000
Developer: 400

This is subjected to change, check the below link for update info

https://developer.salesforce.com/docs/atlas.en-us.salesforce_app_limits_cheatsheet.meta/salesforce_app_limits_cheatsheet/salesforce_app_limits_features.htm