Common snap button for clothing pairings include:

Size 20 snap buttons (about 1/2 inch or 12mm in diameter)

Often used for medium weight fabrics like denim, canvas, etc. This is a very common general purpose size.

Size 24 snap buttons (about 5/8 inch or 16mm)

Used for thicker, heavier fabrics. Can also be used for reinforcement on thinner fabrics.

Size 16 snap buttons (about 3/8 inch or 10mm)

Used for lighter, thinner fabrics. Common for shirts, blouses, etc.

Prong snap buttons

Have prongs on the back instead of a simple stud. The prongs grip into the fabric for a very secure hold. Often used for high-stress areas like crotches, armholes, etc. Come in a variety of sizes.

Snap tape or snap by the yard

Pre-attached snaps on a tape or ribbon. Can be sewn in or ironed on. Provides an easy way to apply a row of snaps. Comes in a variety of spacings and sizes.

Decorative snap buttons

Come in a variety of decorative shapes, colors and coatings like enamel. Used when snaps also serve an aesthetic purpose. Sizes vary.

Heavy duty snap buttons

Very durable snaps made of stronger materials to withstand greater stresses. Used for things like overalls, workwear, bags, horse tack, etc. Tend to start at around size 20 and go up to size 50 and above.

The commonly paired sizes are 20 with 24, 16 with 20, and heavy duty snaps for high-stress needs or decorative snaps for appearance. But in the end, the snap size used depends on the specific requirements of the project and the fabrics involved.