The below databases are great for those who are new to finance or want easy-to-use platforms to perform company research.
Hoovers
Mergent Intellect
The below databases are widely used by professionals in finance and related industries. They are useful for performing more complicated financial analyses, charting, modeling, etc.
Bloomberg
Capital IQ
LSEG Workspace
Wind
These databases are widely used by professionals working in private equity and venture capital.
Pitchbook