Here are characters tagged as 'heavier'. But I'm a bit puzzled as to what you mean with 'healthier than normal'?
Hmm, and the art style of Azumanga Daioh makes the girls a bit broader, especially Yomi, who battles with her weight.
Hope this helps!
If you are a bit chubby, and have an oval face -> Lulu from FFX is nice because her costume will make your body conform if you make it right (and can be uber comfortable!!)
If you like it: Rinoa from FFVIII will also make up for any chubbyness (her costume is really nice because it shows the curves (tightens at the most flattering points)
Also: Seras Victoria from Hellsing (either version). Her outfit is good for girls with a bit of chub as she is a bit chubby as well
If you want to cosplay anyone, not really mattering their size, but are worried about your legs being a bit on the chubby side, wear skin colored tights and spanx on top (i.e. over your belly)... it thins out everything and also helps paler girls look less so ^.-
These are just ones I find worked for me (but I also don't mind showing some skin [and I was 5'4" and 160 lbs at my top weight])