Main story missions are not the only attraction offered by Metal Gear Solid V. In addition to matters related to Mother Base, you can spend your time in some other ways. Most important additional activities available in MGS V on which you should focus are:
- Side-Ops - there are 157 side operations available in the game and access to them is successively unlocked. Some side missions can be completed during the main missions. Others are more separate jobs and they are selected similarly to the main missions, from the list available when you're in the helicopter. If possible, try to complete the side ops as early as possible, they will allow you to obtain cash (GMP), rare plans or recruit new important characters (for example, foreign translators).
- Diamonds and resources - You can collect diamonds and resources at any time you want, for example during main missions or while exploring the map. Look for them mostly in villages and enemy bases. Some of them (for example, plants) can be found on open territories, away from any buildings. It should be noted here that resources, from the moment they are found, remain marked on the world map. They regenerate after a time and you can return for them to collect them again. This is especially recommended in the case of rare materials, needed for the expansion of the HQ and for the development of new inventions.
- Secrets - there are many secrets to unlock in Metal Gear Solid V. Similarly to diamonds and resources, you are free to choose when you will collect them. Focus mostly on cassette tapes, posters, blueprints and memento photos.
- Hostages - Saving hostages is often required for completing main or side missions. However, you can also look for them on your own. Each time you reach larger enemy base, try to find the prison and check if there is anyone to save inside (you can "fulton" them or get them to the extraction point). Freeing the prisoners is usually well rewarded (more cash, new base personnel, higher rank at the end of the mission).