We have not described all the existing SKDs, but the mentioned engines allow you to create games from scratch. However, there is also software with which you can improve a current project. For example, you can use Unity Ads
, IronSource, or Applovin for monetization and ads, and MOAT Analytics, AppsFlyer, and Crashlytics for getting usage data.
There are free and paid SDKs. When choosing the right option for you, do not rush to conclusions and do not refuse paid ones if you are on a budget. We recommend that you take advantage of the trial versions of the platforms that suit you and see what works well for you. While free solutions save money in the first place, paid ones tend to be better optimized and offer out-of-the-box tools for scaling and porting apps, so they can be more profitable in the long run. It all depends on the complexity of your project and plans for further development.