At the beginning i want to apologize for my English.
This is going to be my first arduino project and I have some questions. I want to operate on 4 stepper motors (e.g.). Is it possible to use two of these on a Arduino Uno Rev3 / Arduino Leonardo.
On the Internet I found that 4 EasyDriver Stepper Motor Driver could work, which option is better?
Next question, if it is possible,will be there some "slots" left so I be able to connect light sensor and one servo (servomechanism).
Motors wont be used at the same time, so I dont think power will be an issue (correct me if I'm wrong 
)
The main concept is that, every single motor will do his part (e.g. motor 1 half step then motor 2 full step and so on) then servo will move if light sensor detects light.
Greetings
Is it possible to use two of these on a Arduino Uno Rev3 / Arduino Leonardo.
Yes.
f it is possible,will be there some "slots" left so I be able to connect light sensor and one servo
Not sure what you mean by slots but yes you can control them at the same time.
so I dont think power will be an issue
No idea because you haven't said how you will power them.
p-hello:
On the Internet I found that 4 EasyDriver Stepper Motor Driver could work, which option is better?
I would choose the EasyDrivers as they give you a lot more flexibility at the expense of a little more installation complexity. Also, if you accidentally damage one of them ...
You might want to look at this interesting advice about a suitable power supply. Obviously you will need to adjust the values from the BigEasydriver to your smaller Easydriver.
...R