
Hi @Roma Patel,
Thank you for posting in this community.
Per my knowledge, there is no way to change the background color of the List Web Part. Actually, List Web Part has no background color, white is the background color of the site. You can change the background color of your sites by modifying the theme of the sites.
You can use some of SharePoint's out-of-the-box themes through this article (Select a modern theme),
or refer to this article (How to configure and apply a custom theme in SharePoint Online) to customize your theme.
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Please note that changing the theme affects the background color of all pages in site.
This is the background color of List Web Part after I used a custom theme:
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