Comprehensive size list for IKEA screws and nuts

Screw bit:
Pozi #1, #2*, #3
Hex (metrics) 2mm, 2.5mm, 3mm*, 4mm*, 5mm*, 6mm, 8mm
At least one slot

Nut socket (metrics):
7mm, 8mm, 10mm*, 13mm*, 16mm, 17mm, 19mm

* Used very frequently.

Source: http://www.icomp.webcms.se/index.cfm