You can share all the assets within a folder via a single link or email. To do this, simply press 'select all' then hit the share button in the top right of the Media Library view. This will generate one link or one email that allows your client to view all those assets and jump between them as they need to.
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You can view our tutorial for this here: How to Share Multiple Assets.

Alternatively, you can create a team member with guest access, only giving them access to specific folders.