Sure. I did make a chart on the last slide of the seemingly relevant vitamins, etc. But I don't feel fully qualified because there's a bunch of other vitamins and stuff in some of the greens and I don't know if any of them particularly matter for red-eared sliders. If anyone else has thoughts I'm more than happy to hear them.
So, if you look at that chart I made you will see the Calcium / Phosphorus ratio highlighted (I just divided to make a ratio), because, according to the nutrition section of this site, RES need calcium and phosphorous but should always have more calcium than phosphorus.
In order of highest to lowest ratio:
Turnip greens (4.5)
Dandilion greens (2.8 )
Green leaf and Red leaf (~1.2) (interstingly different in some respects, but not this. Red leaf has much less Vit C than green leaf or Romaine, apparently)
Romaine and Butterhead ~1.1 and 1.0 respectively
Then green beans, carrot, iceberg lettuce, and green pepper, in descending order, all below 1 (so more phosphorous than calcium)
I was most surprised by the big difference between green & red leaf lettuce and turnip & dandelion greens. So far I don't think Sedge liked either of the top two though...
The amount of a few other vitamins varies a bunch (and I am not sure of their relative importance):
Vit C (highest in bell pepper, turnip greens)
Vit A (highest in green leaf, red leaf, romaine, carrot, turnip greens, dandelion leaves)
Vit K (highest in dandelion greens and turnip greens)
Butterhead has a bit less of some vitamins, but it seems reasonably close to romaine in terms of nutritional profile. This is of interest to me, as they tend to have butterhead at the farm. Unfortunately I could not get much info on oak leaf lettuce.
I'm also less sure about the smaller amounts of potassium, magnesium, and some other stuff.
Also, I have no idea if it matters at this scale, but carrot and dandelion leaves are highest in calories. But also highest in carbs (dandelion greens are the highest in fat and protein calories, too). Lowest in protein are iceberg and bell pepper.
How's that for an overview?