Done as part of a 30 minute class.
I'm a little hesitant to critique as you are clearly much more skilled than me! I love the way you are using line weight to give depth to these poses, even with a very economical style. I think you have done an especially good job with this in the figures top right. The heavier lines towards the bottom of the contour give a great sense of weight to the pose.
I love your heavy areas of tone in the bottom right studies, and I think they would be even stronger if you could bring in the same sense of weight here. The deep contrasts can wash out the impact of your line weight a little, and make it harder to see where the centre of gravity falls. For example, in the very bottom right it's tough to see if he is laying down or standing on one leg.
I think your five-minute studies have a really nice happy medium. The tone seems to be much more in harmony with the centre of balance in the pose and it works really well!
it would help the critiquer for the artist to have a goal you have in mind so we could help you.
i am not sure if you chose to focus on specific body parts for the one minute poses but it seem that the head is missing from most of them. if you want to improve on gesturing just know that the head is the control center for any person so draw the head.
regarding the 1 min pose, i like that you denoted the sacrum using 2 dots as a landmark for the pelvis. the rib cage is twisting backwards into space and i like that you created a little overlap with the lines for the model's left arm but i wish you did the same for her right. perhaps you tried to create an emphasis in direction of the pose but i think it is helpful for you to draw a line of how the neck connects to the right shoulder.
the connection from the rib cage to the pelvis right now is one continuous line i believe you can draw some more lines to denote the TWIST in the trunk.
i'm no master on lighting so i won't comment on the long poses but i can see that you're generally keeping the light source coming from one direction.
i think you will get feedback sooner if you include what you want to improve on in your profile