Toddler/Preschool Activity Bags

I've decided to bite the bullet and start actively preschooling D. By
which I mean turning our home into more of a Montessori environment
than the chaos that it now is. To that end, we're garaging most of his
toys (not his trains, of course, or his seasonally almost appropriate
arctic animals), and I'm going to start providing him with activity
bags.
A quick google search this afternoon gave me lots of ideas, so here
are the ones I whipped up tonight:
Matching UPPER and lower case letters. I found a decorated chipboard
uppercase alphabet at Target for $.99, and then I wrote the lowercase
letter on a blank index card. D will match the upper and lower cases.
Since some letters (a, g...w) are tricky, depending on fonts, I put a
different version of the lowercase letter on each side of the index
card;eithe will count as D doing it correctly. I also drew a line
under all the lower case letters so d could more easily distinguish
between d, b, p, and q.