I would suggest the Masiakasaurus, because of the unique jaw that is has teeth protruding outwards. Its main attack could be a quick bite that would have a three second bleed. The secondary attack would be a larger bite that would leave a broken bone effect akin to that of a Carno.
Masiakasaurus
The other creature I would recommend would be the Tanystropheus, which is unique for it's very long neck, and small body. Its main attack could be a normal bite, with the alternative attack that controls the neck, which could be used to fish, or be used as a tool to get to higher surfaces. the saddle could have a rope ladder that lies on top of the neck. To balance it, you could shorten the neck and have it elongate when you use the alternative attack.
Tanystropheus
I just thought these dinos were pretty unique, and wanted to put them out there.