I am not a mechanical engineer, but I have guided several similar projects. We have also published a paper. In fact, any component can be designed and optimized using MATLAB, for example, gear, hook, helical spring, leaf spring, etc. You have to formulate the objective function and constraints. However, for some of the components, the resulting problem may become trivial, not appropriate for final year project. You can refer the book: "Engineering Optimization: Theory and Practice" by Singiresu S Rao or any other book containing design problems. The codes of advanced algorithms like GA, PSO, etc. are freely available. Moreover, "optimtool" function of MATLAB is also highly useful.