TripList is described as 'packing list app that helps you pack better and faster than ever before. With TripList you will spend less time worrying about what you did or didn't pack and more time on the things that really matter'. There are three alternatives to TripList for iPhone and iPad. The best alternative is Packing Pro. It's not free, so if you're looking for a free alternative, you could try uPackingList Free or Packr - Travel Packing Checklist.
You can create and maintain unlimited number of lists of necessary items which you can choose from built-in items catalogue, which is simply customizable for your needs. An app adapts to your request, takes into account the place and the weather and helps to collect things.