How did other Ummas use to fast, since I know the signs of Muslim's fasting, where it is not only fasting from food, but also fasting anything that is not good, I also know that Mariam (Alyha Assalam) fasted when she delivered Sayyiduna Isa, Zakariya (Alayhi assalam) did fast when he had the revelation from Allah that he will be fathering Sayyiduna Yahya (Alayhi assalam) but what other type of fasting they performed.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Allah Says (what means): {O you who believe! Fasting is prescribed for you, as it was prescribed for those before you, so that you may attain piety.} [Quran 2:183]

This verse shows that fasting was also prescribed for people who came before us (Muslims). Actually, we do not know of a Hadeeth stating who those people were or how they observed the fast. Some interpreters of the Quran reported some narrations from some of the Salaf (righteous predecessors) on this topic. It was narrated that Ibn ‘Abbaas said: “Those are the People of the Book – Jews and Christians.” Ibn Mas'ood and others said: “They used to fast for three days every month, then this was abrogated by the Quran.” Al-Hassan Al-Basri said: “Yes, by Allah, fasting has been ordained on all the nations before us as it is ordained on us, one full month.”
As concerns the fasting of Zakariyyah and Mary, may Allaah exalt their mention, it was abstaining from speech, for the lexical meaning of Siyam (fasting) is to abstain. Allah Says about Zakariyyah (what means): {Your sign is that you should not speak to men for three days except by signs; and remember your Lord much and glorify Him in the evening and the morning.} [Quran 3:41]

Allah also Says about Mary (what means): {And if you see from among humanity anyone, say, 'Indeed, I have vowed to the Most Merciful abstention, so I will not speak today to [any] man.'} [Quran 19:26]

Allah knows best.