the other aspects such as color, special design and material as obviously natural materials are better than synthetic ones, depend on your personal preference and your budget, the most important aspects that you should look in a mat before buying it is firmeness, gripness, and size
It is highly recommended using your own mat for hygiene reasons and especially during this pandemic crisis if you have no other option to use an existing mat on your yoga venue, make sure you take your spry sanitiser or disinfectant wipes to clean it before use.
Hope this helps you on making your decision, as you need to balance your requirements based on your personal situation such as injuries, age, the type of yoga, floor and your budget.