Haven’t seen anything like this on the web (correct me if I am wrong), so I decided to create my own.
What is Open Player Controller?
Open Player Controller (OPC for short) is a free and open-source character controller built from the ground up on top of RigidBody.
Why should I use an OPC over other character systems?
While Unity’s RigidBody Character Controller is awesome, it’s an overkill for some developers and is not as compact. E.g, why do I need mobile input for my desktop game?
OPC aims to be flexible and modular, that means, if you don’t want the player to jump or crouch in your game, you can by simply deleting/disabling a jump script.
Oh, and did I mention that every player feature (crouching, jumping etc.) are neatly organized into separate scripts?
OPC is especially useful for developing prototypes for your games, without any need to write your own solution.
Finally, OPC is open-source and free! So if you’re tight on budget, consider using OPC for your current project.
Where can I download OPC?
You can check out the GitHub repository here: GitHub - ElmarTalibzade/OpenPlayerController: Open Source RigidBody Based Player Controller for Unity Engine From there, simply follow instructions in the README.MD file
Help me make OPC better for everyone by forking it on your own repository and doing some improvements there.
You can check out current and planned features of OPC on the public Trello Board here: Trello
I hope you’ll enjoy using it 
Elmar