I just purchased Assorted Greetings and it has some great sentiments for the inside of cards - though I noticed in looking through the gallery some of the cards used those sentiments on the outside of the cards - they work for either. There is also a set called Birthday Greetings that has some great sentiments for inside. Sometimes I just leave the inside blank so I can write a personal note. My handwriting isn't the best, so I tend to write big so it pretty well fills the inside of the card where the sentiment might be.
I usually write a personal note on the inside. I'm not always good with words or coming up with something at the last minute so, like Judy, I will write big! LOL!! I have also started decorating the insides of my cards a bit. Usually just along one side and sometimes I add another layer or 2. I'm primarily a CAS stamper so the inside isn't too elaborate.
I do use the Birthday Greetings a lot for inside sentiments. Will have to check out the assorted greetings.
I have to Assorted Greetings and Birthday Greetings & use both a lot. I also will look on the internet for card sentiments, find something appropriate then type it in Word, print it on linen paper & adhere it to the inside. Like others have said, I'm also not good at coming up with something to write inside.
Thanks to Microsoft Word, I design the inside on the computer. I like that I can say exactly what I want and personalize it for specific people/situations. There are so many amazing, free fonts available, too. I often repeat stamped images from the front of the card on the inside to pull it all together.
Here are a few sets that Gina has. There are others as well.
I Hope that helps. Like I said there are others. and you can hand write or type up your own if you are good at writing stuff like that. I'm not so I use these sets! LOL :) <3 Here is a link http://www.shop.ginakdesigns.com/category.sc?categoryId=37