Source: Tafsir al-Ahlam al-Kabir (Ibn Sirin)
Fat in a dream indicates wealth, fertility, and goodness. Eating it indicates eating from a noble man's wealth. Fat from a dead animal is unlawful money.
Source: Ta'tir al-Anam fi Ta'bir al-Manam (Al-Nabulsi)
Fat indicates knowledge for scholars and marriage for the unmarried. It may also indicate an adulterous woman.
Source: Al-Isharat fi Ilm al-Ibarat (Ibn Shahin)
Fat is interpreted as wealth and benefit. Whoever sees himself melting fat is spending money on a good cause.