The 18650 (18mm Dia x 65mm long) is the commonest size Lithium...

The 18650 (18mm Dia x 65mm long) is the commonest size Lithium cell available, fitted to everything from solar lights to earlier Teslas among many other things. They are slightly larger than an AA cell and store about 2 to 3.5 Ah.

The 32600 (32mm Dia x 60mm long) is another package sometimes found in power tools and are longer and narrower than a C cell. They store 5 to 6 Ah depending on the manufacturer.

The 2170 (21mm Dia x 70mm long) cell (4.2 to 5 Ah) is used in the Tesla Model 3 but not common yet. Tesla will probably swap the S and X packs across to it in due course. Its energy density in terms of weight and volume isn't much different than their 18650 cells but it can accept charge at a higher rate which is important for EVs.

The 20700 (20mm Dia x 70mm long) was introduced as a successor to the 18650 but hasn't gained traction yet and may not with Samsung and LG Chem now producing the 2170 with Tesla.