Model	Year	Description
Yashica A	1958-1969	3-element Yashikor. B, 1/25 ~ 1/300. Red-window film advance
Yashica B
Yashica C	1957-1958
Yashica D	1957-1973	Early production with Yashikor. Later switched to the better 4-element Yashinon. B, 1 ~ 1/500. Film advance knob. Shutter cocked separately.
Yashica E	1964-1966
Yashica 24	1966-1968
Yashica 12	1967-1968
Yashica Mat	1957-1971
Yashica 124	1968-1971
Yashica 124G	1970-1986

There are also other models such as Yashica LM, Yashica Mat EM, Yashica Mat LM etc. Currently the 124G model is the hottest Yashica TLR on auction sites. But, I think the build quality of the 124G is not as good as the old models. As long as the lens used is Yashinon, the Yashica D, Yashica Mat, and Yashica 124 etc models are priced more reasonable. Try to avoid models before Yashica D, though.

These are the most commonly found lenses on Yashica TLRs.

Tri-Lausar & Yashimar
3-element design. I haven't tried these lenses. But from what I heard, these lenses are not as sharp as the Yashikor.

Yashikor
Also a 3-element deisgn. Coated. Give good result when stopped down.

Yashinon
If you want to get serious with your TLR, this is the lens to look for. Copy of the famous Zeiss Tessar design. 4 elements in 3 groups. Coated

Lumaxar
Lumaxar was the original name of Yashinon. The design is the same. So you can expect it gives the same quality as the Yashinon.

    

The models I have came with X and M sync. Some models only with X sync.

Early models use knobs for film advance. Shutter need to be cocked separately. Later models use levers and the shutter is cocked automatically during film advance.