Try different things. Not everyone has ideas out the wazoo. There are solutions. These include but are not limited to ...
* Poses for artists. There are many websites and books of poses you can draw or paint.
* Buy one or more poseable dolls, mannequins, or other desktop art models. Move them around until you like the poses, then draw. Or put them in freaky poses and try to imagine how they got that way.
Put them all together and you can't help noticing the almost complete lack of variation in body size/shape. Just in case anyone wants a side job, consider building art mannequins with diversity.
I tried searching dolls, fashion dolls, and even ball-jointed dolls. I only found a few images of diverse body types, and some projects that failed before reaching market. The "realistic" or "natural" bodies are only slightly thicker than typical idealized shapes. >_< If you want to find a fat poseable mannequin, my best suggestion is go to a doll shop and ask an expert, who may have advanced references for the obscure stuff that isn't always for sale.
On the bright side, Creatable World dolls come in various ethnicities and hairstyles, and can change gender presentation. They're a little less flexible but a lot more realistic than most poseable art models.
Or you could just make your own:
* Use photos from magazines. Sport magazines are especially good, but any magazine with people in it will work. Here there is more diversity. Or add some wildlife magazines to mix up your subjects.
* Get together with a few friends and draw.
Invite artist friends and take turns drawing each other. This is especially fun with gesture drawing where you only have to hold a pose for 1-5 minutes. See who can strike the zaniest pose for others to copy.
Invite theatrical friends to act out scenes until you see something you like. Let them pick a sketch to keep for their portfolio.
Invite friends who are into fashion design, fibercrafts, sewing, etc. to show off their stuff for you to draw. Let them pick a sketch to keep for their portfolio.
Invite photographer friends. Mixed with any other types, they can shoot reference photos for everyone to share.
* If you want to do something different from figure poses, try still life. It can be really fun to find things that are interesting to draw.
Some artists like to collect things for this purpose, and a still life collection can look really cool just sitting on a shelf. Some fairly normal things:
But don't stop there. Get some bizarre stuff -- broken toys, random hardware parts, fabric scraps, oozes, skulls, pottery that you can drop and sketch the broken bits, etc. Thrift stores, antique stores, and junk shops are all great places to look. Etsy and eBay often have "box lots" of small items intended for craft use. If you also work with live models, you can use your theatrical props for still life art also.
* Art prompts.
Many websites and some books offer art prompts. These are usually text phrases, but sometimes you can find random lines to expand upon.
* Art exercises.
These sometimes have a skill focus. The weird ones are very good for breaking blocks.
* Skill practice.
You don't have to draw "things." You can practice lines, shading, perspective, tool control, or other techniques. I collected a bunch of worksheets and skill resources here: