Nafil Salaahs are very beneficial and important, it is an optional prayer which a Muslim can pray and get rewarded in the world afterward. We often miss this Salah by just labeling them as "optional" but these are something we should consider as a gift from Allah Azawajal.
1. Ishraaq Salah
It should be performed 15 minutes after the sunrise.
It usually has 2 or 4 raka'ats.
Benefit: This can give you a reward of one Hajj and one Umrah.
2. Salatul Taubah
It should be performed when the need arises.
Usually has 2 raka'ats.
Benefit: If you pray it with all of your heart and with a truthful heart and sincerity then Allah Azawajal will forgive the sins, if Allah wish.
3. Salatul Istikhaarah
It should be performed at any permissible time.
Usually has 2 raka'ats.
Benefit: This Nafl is best when you are asking for the Allah's guidance over your decision.
4. Salatul Hajaat
It should be performed only in the time of need.
Usually has 2 raka'ats.
Benefit: It is the best for seeking help from Allah when you're in the need or in any kind of difficulty.
5. Tahajjud Salaah
It should be performed after Ishai prayer, later part of night.
It usually has minimum of 2 raka'ats and maximum of 12 raka'ats.
Benefit: This Nafl is best when you are asking for Allah's decision for yourself.
6. Salatul Chaasht
The best time for this Nafl is some part of the day (10:00 am) has passed until zawaal.
It can be of 2,4,6,10 or 12 raka'ats.
Benefit: You will be counted among Allah's loving people.
7. Tahiyyatul Wuduhu
It should be performed after wuduhu
It has 2 raka'ats.
Benefit: You are entitled to enter Jannah.
8. Tahiyyatul Masjid
It should be performed upon entering Masjid (mosque) before sitting down.
It has 2 rakaats.
Benefit: The Nafl Is to honor Allah Azawajal.