How to say 'That's all' in another way that is polite and informal?

Question

Answer

a) this is [more or less] all I planned to tell about {XYZ, the subject}.
Thank you for following my exposition.
There is some time  left, if you have questions related to the subject, 
I will be glad to answer.

b) I did my best, now please go away, I am tired of seeing your dumb faces having
difficulties following my great ideas. :)

Answer

你可以说That's it或者I'm done，再地道点的就说一个Period就行了，同时这还有“没啥可说”的另一种意思