Many hand quilters use "betweens" - they are very short.
The bigger the number of hand sewing needles, the smaller/thinner they are.
I like 11 John James needles. When I can't get an 11 threaded, I go up to a 10. The number 12s are very thin and slide in and out of the fabric easily - but sometimes I can't get the things threaded.
Number 9s are still small and thin.