Summary
250 screws, a random selection of "the most popular" smaller sizes for watch movements.
Click here to see 1000 larger screws for watch cases, spectacles etc.
See an information article, A Short description of Screw Types.
Will we have the size you want?
PLEASE do not send the measurements and ask us to look through the box and measure them. I did once try this, using a measuring microscope, and calculated that it could take many hours to find an exact match (there are thousands of screw types - length, diameter, head type, thread pitch...)
There are 500 screws, and they are the most common sizes for watches, and there is a fair chance that you will find the one you want (I have twice found just the right size for a watch I was repairing) ..but not guaranteed.
My best suggestion is: buy them, and if you don't find the screw you want this time, then maybe you'll find one for your next job.