Since my son doesn't go to consistent daycare I try to incorporate learning activities into the time we have at home, which usually means disguises learning activities as games and toys. Currently I've been finding ways of interesting my son in writing and solidifying his knowledge of the alphabet and these are the tools that have been most helpful.
We were gifted these for a birthday a while back, My Favorite Things Flash Cards, and they're pretty perfect. Plain letter on one side, and an illustration on the other. Big enough to trace with a finger too.
Just your run of the mill cookie sheet straight from the pantry. We've been using ours for "salt letters" and other games.
Movable Magnetic Alphabet
This is a find I'm quite proud of. I love the look and the idea of real Montessori moveable alphabets, but dropping $50 on just lowercase letters alone is not in my budget. After days of searching for a reasonable alternative I finally found what I was looking for at Lakeshore Learning. Originally I found this company through amazon.com, but Amazon didn't have exactly what I was looking for so I searched for the company directly and was more than pleased with what I found.
I was looking for upper and lower case letters, but still in the blue consonant/red vowel color scheme that a real moveable alphabet comes in. Lakeshore had just that, for about $7 a pack for each upper and lowercase (I got two lowercase and one uppercase pack, so just over $21 for a complete set)
I also picked up a set of the word building tiles as well - for three dollars it was great price to try them out. They're a little on the small side, and only lowercase, but not a bad tool to have around and probably the cheapest way to get a movable alphabet at $3 for the set.
Lakeshore also offers, what appears to be (I do not own these), a nice resource for "Tactile Letters" or sandpaper letters, but I haven't added these to our collection yet because our large alphabet flash cards have been doing the trick.
That's what we're using so far!