Ask HN: How can I find org charts of top tech companies and startups?

Mandatory link to a classic http://bonkersworld.net/organizational-charts

Discoverorg.com is a paid service but gets you org charts and contact information. It's pricey so not a fit for small sample sets but if you are looking for information and contact details on lots of companies it's worth looking into.

Zoom info, data.com and LinkedIn can also be used.

If you have a specific list you are targeting a researcher hired off of upwork might be a good option at a decent price.