I love the keep it simple line from PTI...I agree. I love the varying fonts and sizes for a single good sentiment and it is a great value. I have the surgery set and the get well sets.
I have found I can multi-task sad looking characters for get well, miss you and sorry...
I just got a set from Unity with the big sale called Just....sorry. Girl under a blanket. Could be a bunch of things.
If you want humor I would look at Art impressions. One is Get better soon.
Anything with a character holding flowers.
Injuries: AI has 2 sets-one for women, one for men (swagger). High Hopes has Troubled Travis (banged up dragon).
Crackerbox also has done actual Covid virus stamps...
Rabbit hole's caffeinated critters-I have the owl since he just looks miserable.
Inkadinkdo has a couple of mice-one signing of the casts of the other
House mouse has a few images.
I would look over at Unity bc of their huge sale and Impression Obsession is also having one.
Also look at ebay-I got a number of older images of critters in bed there.