I've made a number of sets of these over the years and they are always a big hit. They're easy enough for kids to help make, easy to customize, and super useful. I mean, you can never have too many magnets.
These are made from 3/4" magnets. You can find an 18 pack of them for $1.99 at most big box stores.
I create and print out whatever words or pictures I want on white card stock. This year I used my Silhouette Cameo (and Silhouette Studio software) to do my designing, printing, and cutting, but in the past I've done my designing in Word and used a 3/4" circle punch to punch out the words.
Use some really strong clear glue (I like to use E6000 glue for this task) to attach a clear glass rock to the top of the magnet. This protects your design and has the added benefit of magnifying it a bit, too.
I like to package the up in groups of 3 in a little clear favor bag with a bit of matching ribbon. You can gift them just like this, or add them to a gift basket.
How are your handmade gifts coming along this year?