Cheap flannel backed table cloths from the dollar store. I have 2 hanging side by side. Easy to change out when needed.

Mine is a piece of insulating sheeting (with the pink panther on the back) from Lowe's, with batting duct taped on it. I cut it down a bit and it leans against my closet door. I am very happy with it. Let me see if I can find a picture of it.

Okay, found two...

I used fleece as well. I made it different to my wall, but the fleece like flannel holds most blocks well. :)

Fleece, flannel, or flannel backed tablecloth work equally as well.

Ditto insulation - 4'x8'x2" covered with flannel sheeting

I like a tri fold kids science project board that I covered in felt. It's not large, but they're cheap to make. :)

Mine are insulation board covered with batting. I tried the vinyl tablecloth method, then flannel, but just like batting the best.

I'm planning to use the insulation sheet. I've found the back of a vinyl table cloth works well for blocks, but I'd also like to be able to pin a quilt up for photography.

I have an old kingsize poly mattress pad that I was going to donate to good will. A lightbulb went on & I hung it on the wall to use. Blocks still pretty well, but for anything larger I just stick a pin in the corners.

Yup - same here, and love it. If I need to I can pin blocks to it.