I have a similar problem to OP. I don't know much about writing CSS, but do you know any articles/guides that could offer a bit more guidance on customisation of answer / reply boxes?

but what I actually meant was, can we get the features of using those youtube and image buttons.... like adding a youtube video or an image file directly with a button.

Thank you for using wpForo and for contacting us. 

I'm sorry but wpForo doesn't have such an option. 

If you're familiar with CSS you can do it by yourself. Simply find the classes of the buttons and add the CSS styles you'd prefer. The CSS codes should be added in "Custom CSS code" textarea, located in the Dashboard > Forums > Settings > Styles admin page.

As per the attached image, Is there an option to change the Icons and buttons in comment box of forum.