Toyota nuts and bolts typically follow Japanese Industrial Standards (JIS):
Here are the common ones:
Shank Diameter (mm)....Bolt Head Size (mm)....Thread Pitch....Example
5...............................8..............................0.8................Tailight studs
6...............................10............................1.0.................Battery Tie-down bolts
8...............................12............................1.0.................Pressure Plate Bolts
10..............................14............................1.25...............Exhaust Manifold Studs
12..............................17............................1.25...............Flywheel Bolts
14..............................19............................1.5.................Crank Pulley Bolt
16..............................22............................1.5.................Transmission Drain Plug