Have a look in the Extensions Database. If you can't find one that is suitable you could look in [3.1.x] Extensions in Development, but note that extensions in development are not intended for a live board. If there is nothing there you could have a look in [3.1.x] Extension Requests and if it hasn't already been requested make a request there.
Thanks, but i installed this Extensions, i uploaded alls the files and when i go in the ACP --> Customise -> Manage extensions i don't have got the extensios to enabled, why ? There are my ACP , please help me!
I only followed this guide