Seesaw - the best K-2 portfolio app so far, I have PD materials for this from the company!
I-Nigma - a QR code reader, this eliminates the need for students to have to type in URLs and is incredibly valuable
Geoboard - a simple geoboard app
ABC Magnetic Alphabet - a simple magnetic letter app, speaks words as they are built
Kodable
Daisy the Dinosaur - both of these are coding apps for K-2, to build on our Hour of Code experience
Adobe Voice - an awesome app for making stories, voice/pictures, saves to camera roll (crucial!)
Adobe Clip - for making videos, this is MUCH easier to use than iMovie (but iMovie is still useful for its Trailer-maker)
I would also advocate finding funding for a few apps this year, including LetterSchool, a handwriting app (vetted by our OT folks, works with HWT) and Book Creator, a spectacular award-winning book writing/publishing app.