Hi i’ve written a detailed post on all FNO tools.
You can find it here: Option Trading Tools in India - Compared
For Full time option traders, Quantsapp, with the sheer data that they provide is a mile above the rest. They have Option & Strategy Premium charts along with historical Greeks which is of great help to me.
I found Opstra’s multi strike option OI chart very useful
For beginners I would recommend using Sensibull’s mock trading feature for practice.
My FNO provides a clean all in one screen layout and Is one of the oldest players in the market