pins
sticky tape (scotch tape)/ two side sticky or one side
blue painter's tape
hair grips of various sizes and shapes
large hair grips to attach to excess fabric collecting around embroidery frame
temporary stabilizers with sticky back
clothes pins (pegs)
simple large tacking stitch by hand
paper grips (those used to hold a ream of paper or smaller amounts of paper depending on thickness)
safety pins
paper clips
Send some more ideas in the comments section - we'd love to hear from you.