Points style in Gnuplot

It's quite annoying to find the best points styles for your postscript output from gnuplot. I tried to find the site with list of all points style, but I failed, so made my own:

set term postscript
set output "test.ps"
set xrange [0:30]
set yrange [0:30]
set key right bottom
plot   x+1   with linespoints pt 1 title "1",  
       x+2   with linespoints pt 2 title "2",
       x+3   with linespoints pt 3 title "3",
       x+4   with linespoints pt 4 title "4",
       x+5   with linespoints pt 5 title "5",
       x+6   with linespoints pt 6 title "6",
       x+7   with linespoints pt 7 title "7",
       x+8   with linespoints pt 8 title "8",
       x+9   with linespoints pt 9 title "9",
       x+10  with linespoints pt 10 title "10",
       x+11  with linespoints pt 11 title "11",
       x+12  with linespoints pt 12 title "12",
       x+13  with linespoints pt 13 title "13",
       x+14  with linespoints pt 14 title "14",
       x+15  with linespoints pt 15 title "15",
       x+16  with linespoints pt 16 title "16",
       x+17  with linespoints pt 17 title "17",
       x+18  with linespoints pt 18 title "18",
       x+19  with linespoints pt 19 title "19",
       x+20  with linespoints pt 20 title "20"

The result is below. It was obtained by: convert test.ps test.png (and next rotated):