The first Sun3's were the 3/50 workstations (wide pizza box) and the 3/160 servers (12 slot chassis). The configuration of one 3/160 with several diskless 3/50 was very popular.
Later came the desktop 3/75 (wide pizza box, 2 slots), 3/140 (tower or desktop, 3 slots), 3/150 (tower, 5 slot) and 3/180 (19" rack mount, 12 slot). They were mostly combined from parts of the 3/50 and 3/160.
Next came the 3/110 (tower or desktop, 3 slot) and the 3/E (without any chassis, could be plugged in a VME bus chassis). Both machines weren't very popular so they are quite rare now.
But the next generation of Sun3's, the 3/60 (wide pizza box) and the 3/260 server (12 slot chassis) were the best selling machines. The 3/160 could be upgraded to a 3/260 by replacing CPU and memory. The 3/60 could be ordered with a color graphics card (before only the 3/110 had color graphics).
The 3/80 workstation (pizza box) wasn't actively sold by Sun anymore because Sun now started with the new Sparc series. The machine isn't any faster than the 3/60, but despite this facts the 3/80 was sold in large numbers which shows the popularity of the Sun3 series.
The last Sun3 was the 3/470 server. This machine was again considerably faster than the 3/260. The 3/260 could be upgraded to a 3/460 by replacing the CPU. But Sun's marketing acivities were already focused towoards the new Sparc generation and so the 3/470 is very rare.