Found the answer! Cant figure out how to delete this post :)

Congrats on your first campaign @Danika C :) 

Let’s keep this post here, but would you be able to add how you solved this? Just in case someone else has the same question :)

The way I would have done this (depending on how many people were left off - but let’s say it was a lot) is to create a segment of subscribers who received that email campaign you sent zero times:

Similar concept to a Non-Opener Segment mentioned here in a Klaviyo Help article:

https://help.klaviyo.com/hc/en-us/articles/360048341511-How-to-Create-a-Non-Opener-Segment

Hi Manny,

Yes, I cloned the campaign and then created another segment after adding the people to the list who hadn't been added the first time. I then sent to those who had opened the email zero times as you suggested. It worked. It would be great if there were a way just to send a sent campaign to a few additional contacts, but this works for now.

Thanks for the link!