Personally, I carry everything listed on the class supply lists for the IQA and AQS quilt shows.
Comfortable clothes.
Required supplies for any projects you are working on or workshops you plan to attend.
For extension cord - take a look at the one on the reel. Not expensive and comes with 4 electrical plug outlets.
Surge Protector.
Scissors for paper and fabric.
Portable design wall.
If you have a tin box large enough to hold a pair of 8" scissors then you have something large enough to hold all of your small tools. It can be small enough to be placed on table so that you are not digging for tools when you need them.
Pressing mat and small iron.
Eraser for marking pencils.
Sand Paper Board
Masking Tape
Office Supplies - Paper, Pens, Stapler and Staples, paper clips.
Zip Loc Bags - small and/or one gallon size for scraps, etc.