One of the things I learned very early on in Unity development is don’t reinvent the wheel! There comes a time in any project you are working on that will require a certain feature and you may be tempted to start coding a solution. This path could be costly in terms of development hours when in all likelihood someone has already developed a solution which you can import and make use of.
This is where the Unity Asset Store comes in with a huge amount of assets both free and paid for that can and does save you time and money.
For some years there have been three assets in particular that I import into any new project due to their provision of essential features. The ordering of the list below is no reflection on importance as far as my use is concerned as I find all three stand proud on their own for their features and outstanding customer support.
Easy Save provides all the saving and loading features you will ever need and the support from the author is fast and helpful.
DoTween Pro provides extensive animation features for everything from game objects to user interface components with excellent support from the author.
Cross Platform Native Plugin provides access to the target platform native features such as social media, imagery, email etc. and again the support from the author is both fast and helpful.
So just remember when you are developing and a requirement arises, check the Asset Store first!