I've done these (and probably more that I can't think of at the moment!)

I spy :)
Making collections of items for each letter
Sandpaper letters
Alphabet jigsaws / inset puzzles
Alphabet beanbags
Games like I went to market trying to think of food / clothes / vehicles etc for each letter of the alphabet
Magnetic letters
Foam letters (in water play)

You've prob thought of all of those though?