From Fripperies & Bibelots stitch markers with clasps! They fit nicely on needles up to 4mm thickness and they can also be attached to stitches, for marking rows or individual stitches... so they work great for crochet too!
Check photos for number of markers in each pack.
Little Ducks and Inner Glow, are approx 2cm long
Dragon & Mermaid are 1.5cm long
Blue & White China are 2.5cm long
All measurements exclude the clasp.