As a collector/user who has photo gear going back to the 1840s, I'll take a stab at it.
1. Giroux sliding box camera, 1839. The first commercially available camera (generally made Daguerrotypes.)
2. " Mousetrap" cameras, 1839, invented by Henry Fox Talbot. (Made calotype/salt prints.)
3. Lewis camera 1851, first camera with a bellows (generally used in wet plate photography.)
4. Dallmeyer stereo camera (1861), first successful commercially available twin lens camera, really got the stereoview genre rolling.
5. Graflex (Folmer & Schwing), 1898, first camera with high speed focal plane shutter (1/500s, 1/1000s). A true breakthough!
6. Kodak Brownie, 1900, introduced photography to the masses
7. Kodak Vest Pocket, 1912, first successful pocket sized folding camera, favored by several early explorers
8. Leica (invented 1913, produced in 1924), a quality pocket sized camera taking 35mm film. Interchangeable lenses 1933. Latest generation still in production.
9. Kine Exacta, 1936, (35mm), introduced the form most cameras still use today, interchangeable lenses
10. Hassleblad 500C, 1959, small sized professional camera with Zeiss interchangeable lenses
11. Nikon F, 1959, revolutionized camera design (a form still most common today.)
12. Topcon RE Super, 1962, first mass produced camera with TTL metering
13. Polaroid SX-70, 1968, first camera with autofocus
14. Kodak DCS, 1991, first commercially produced digital pro camera
15. Canon EOS D30, 2000, first popular DSLR
16. Hassleblad HD1, 2004, first dedicated MF digital camera.
I own several of the above cameras, and they are just as exciting to use now as when the original owner had them!
Kent in SD