With your support I managed to win the election. Thank you for that.
I'm not sure what an autonomous sentence is, but if someone has performed a service for you, such as helping you up after falling, you'd say 'Thank you for that'.
If someone gives you a cheque for £100 to pay a bill, you'd say 'Thank you for this'. Or a bunch of flowers - 'Thank you for these'.
Student or Learner