It's a great setting for a sampler quilt.
I would guess that those blocks are 9" set on point. Maybe even 12" but they don't look that big.
The block size would need to conveniently accommodate blocks with 3x3 AND 4x4 grid designs.
I split the blocks into the two groups - defined by the blue and green outlines.
If look at each group individually, you can see, as krafty14 mentioned upthread, that the sub-units of each block are made up of a few common configurations (HST, QST, FG, 4patch).
So once you decide on the block size, then it really wouldn't be difficult to figure out the size of the components - even if you didn't know the block name.
I have no idea what your skill/comfort level is, but if you're a relative beginner, this project would be a terrific way for you to hone some pretty basic skills that would serve you well for almost any traditional/block-based quilt you make in the future.
Just post here if you need/want more info.
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