One possiblity would be to use a product feed to dynamically populate the block with collections based on the person's recently viewed items or popular categories. You can create a CSV or XML product feed containing all of your collections or product categories and their associated products, then import the feed into Klaviyo and use it to populate a dynamic block.
OR
Use Klaviyo's "Product Block" feature: You can use Klaviyo's "Product Block" feature to dynamically populate a block with products from a specific collection or category. To do this, go to the "Templates" tab in Klaviyo and select "Create Template". Then, select "Product Block" as the block type and choose the collection or category you want to display. You can also customize the block's appearance and add dynamic variables to show personalized product recommendations based on the person's behavior.
OR
Use Klaviyo's "Smart Send Time" feature: Klaviyo's "Smart Send Time" feature allows you to send emails at the optimal time for each recipient based on their individual behavior. You can use this feature to send personalized emails that include dynamic blocks with product recommendations based on the person's recently viewed items or popular categories.