Stainless Steel Sheet Metal Screw, Plain Finish, Flat Head, Phillips Drive, Self-Drilling Point, 1-1/4 Length, #6-20 Threads (Pack of 100) by Small Parts : Amazon.co.uk: DIY & Tools
Socket Screws: Everything You Need to Know | Leyton Fasteners
Multi-purpose Wood Screw - 4.0mm x 40mm (Pack of 200)
Siniat Self Tapping Screw - Siniat
A few common screw head types and what they are used for - UC Components, Inc.
Screws Buying Guide | Screwfix
Headless Screw with Right Hand or Left Hand Thread - Jakob