Mine are:
#1 a good sewing machine that is dependable, does the quailty stitch straight needed and trouble free.
#2 quailty thread, there are only 3 brands I use now.
#3 sewing machine needle and use the right one for the fabric, thread and needle size needed for what steps you are doing for your quilting.
#4 a great ruler, rotary cutter with a sharpe blade and mat.
#5 a good seam ripper...lol for those mistakes
Well I guess I need more then one!!! lol