This is a pillar found at Shri Ram Temple excavation in Ayodhya, Uttar Pradesh.
The part in red colour is a Poorn Kalasha(पूर्ण कलश) which is a symbol of prosperity in Hinduism.

Source: Namo Bharath

More clear image:

Cobra!
Why Cobra?

शिवाय विष्णु रूपाय शिव रूपाय विष्णवे |
शिवस्य हृदयं विष्णुं विष्णोश्च हृदयं शिवः ||
यथा शिवमयो विष्णुरेवं विष्णुमयः शिवः |
यथाsन्तरम् न पश्यामि तथा में स्वस्तिरायुषि|
यथाsन्तरं न भेदा: स्यु: शिवराघवयोस्तथा||

Another pillar with Poorn Kalasha(पूर्ण कलश)

This is 'Makara Pranali' with crocodile face
Crocodile is a symbol of river Ganga,before reaching the 'Garbha Griha',1 side,a lady standing on crocodile&other side,a lady standing on a tortoise
This means a symbolic bath in Ganga,Yamuna & Saraswati before entering the main temple

This was the wall below the mosque area.

The Hari-Vishnu Inscription:
This stone slab carrying a 20-line long inscription, It has all the details regarding the construction of the temple.
You can read more about it here: https://www.stephen-knapp.com/ayodhya_and_the_research_on_the_temple_of_Lord_Rama.htm

All the historical evidence of Shri Ram Temple in Ayodhya.

Source: Namo Bharath