All religious scholars are unanimous that that all Prophets kept beards. This is even mentioned in the Qur’an: Allah the Almighty narrates the incident when Sayyiduna Harun Alaihissalam calls out to his brother Sayyiduna Musa , “O son of
my mother! Do not seize (me) by my beard, and nor by my head.” (94:20)
The scholars point out that this is a CLEAR-CUT proof that HARUN had a LENGHTY beard since you can’t seize a beard unless it is long
Ibn Sad reported in Tabaqat al-Kabir (3/16-17, TaHa Publishers):
Yazid ibn Haroon reported from Ismail ibn Abi Khalid that ash-Shabi said: I saw Ali. He had a large beard which filled all that was between his shoulders..”.
al-Fadl ibn Dukayn reported from Yunus ibn Abi Ishaq that his father Abu ismail said: I saw Ali and my father said to me: Amr look at the commander of faithful. I went to him and I saw that he did not dye his beard. He had a large beard“.
Shihab ibn Abbad al-Abdi reported from Ibrahim ibn Humayd from Ismail that Amir said: I have never seen a man with a larger beard than Ali. It filled the space between his shoulders and was white.
al-Fadl ibn Dukayn reported that Rizam ibn Sad ad-Dabbi heard his father describing Ali, he said: A man taller than medium with large shoulders and a long beard..
Imam Al Dhahabi ‘alayhi ramatullah compiled a collection of the description of the Sahaba in his famous “Siyar A’lam Al Nubalaa” THIS is how Ali Ibn Abi Talib looked like:
‘Ali bin Abi Talib:
“He was balding, but had much hair left, as if he was wearing a sheepskin. He was of medium height, with a large belly and a large beard.”
“He had a yellow beard.”
“He dyed his beard with henna once, then he never used it again.”
“His hair and beard were white, like cotton.”
ash-Sha’bi said: “I saw ‘Ali with a white beard, and I never saw anyone with a larger beard then he.”
“He had heavyset, large eyes, and he was closer to being short.”
In the book:“The Beard Between the Salaf & Khalaf” it is said about Ali -radiyallahu anhu- and the size of his beard:
[…] there are authentic reports indicating that the Rightly Guided Successors, as well as other sahabah and tabi’un had
large beards.
Abu Bakr” had a thick beard [Qut ul-Qulub 4:9],
Omar ” had a big beard [Al-Isabah 2:511],
Othman had a large beard [Al-Isabah 2:455],
and Ali’s beard was so wide as to span the distance between his shoulders [At-Tabaqat (3:25) by Ibn Sa’d] […]