If you're part of the 'stationery community' then these will be old news to you, but I recently discovered these wonderful travel friendly and space saving Folio's by Websters Pages. I actually picked this up off eBay as I don't think they're available anymore.
These Folios are zip around cases with sections inside for various items. Personally I keep small sticker sheets, washi samples, pens, paper clips, sticky notes and project life cards - to use as decoration or dashboards - in there.
They're really handy to have as they save so much space on your desk area, or in your bag. They're perfect for long car journeys as well as you can take the necessitates that you need for planning with you.
They are available in a range of colours. I chose the white one, but wish I could pick up some more colours. It's a good idea to check eBay or Facebook groups for these. Be careful that you don't pay too much though as I think these were around the £3 mark when they were first released.
Do you have anything for travelling with? How do you keep your essential stationery supplies together?