I use glucose buddy - excellent app for recording BG, insulin, food and exercise. It does become a little slugish to open when there are a few logs in tho'.
Carbs and Cals is also really good, quite steep at £4.99, but it's all UK based food and has pictures of everything so you can judge your portion size. Most other carb databases I have used have all been based around American food so not that revelent.
The other one I use is a website, which I have a link to on my home screen called "calorie count database"...search for it on google it's the top link. they have a mobile friendly site which lets you search for anything - generally pretty good at the rare-er foods.