Just copied these sizes from an advert for 'top quality' feeler gauges..
"Super accurate, 12 Blade, Metric and Imperial Angled Tappet Gauge with 95mm long angled blades. All blades are hardened and polished for a longer life. Each feeler blade is marked with its size and folds into a polished steel case with thumbscrew. An invaluable feeler gauge set, designed for accurate precision work.
Metric - mm
0.203, 0.254, 0.305, 0.330, 0.356, 0.381, 0.406, 0.457, 0.483, 0.508, 0.635 and 0.660mm.
Imperial - inch
0.008, 0.010, 0.012, 0.013, 0.014, 0.015, 0.016, 0.018, 0.019, 0.020,