There are various tools that can be used as per Business Analysis usage in Different Sectors, also some Companies used their separate tools. However the tools are not limited, it is changing as per the BA working in a particular company.
Below given are a few crucial tools unavoidable for a BA.
1. Very good knowledge of Microsoft Office tools especially Word, Excel, Powerpoint & Access (to a certain extent) which will help in the Requirements writing & Documentation part as well as for the presentation of Documents for the sign-off.
2. Microsoft Visio which is used widely irrespective of the industry for creating the UML diagrams such as the Use case diagrams, activity diagrams, Static Diagram & Sequence Diagram. Also, it is helpful for creating ER models & Brain Storming charts & Flow Charts for Business documents creation.
*Also, a Lucid chart can help (For Non-Windows Users).
3. It is good to know Any BI tool, which will get an edge like Power BI & Tableau.
4. For Prototyping Axure is one of the good-to-go tools.
5. Wireframing tools like Balsamiq are a good choice.
Also, add to this one should have sound knowledge of SQL (RDBMS understanding) & Python (Any language) for more access to Technical roles.