Tables for general engineering

• US screw sizes (incl. recommendations for drilling)
• American drill gauge
• American wire gauge (for electrical wire)

Tables for life sciences

• Microscope cover glass thickness
• Syringe needle gauge

Tables for electrical engineering

• Size table for SMT resistors and capacitors

Useful tables elsewhere on the web

• US drill bit sizes (Wikipedia)
• US tap drill guide (Steven Henderson)
• Metric tap drill guide (ibid)
• Metal gauge chart (ibid)
• US screw dimensions (American Fastener)