Could it be a table topper? They are a square piece of material laid on the diagonal of a table. They're much smaller than the table (or ottoman) so it won't hide the furniture.

I use them and they really make a difference, especially on the dining room table.

It's a doily!

What should be in the tray? Well, what do you use the room for? When you're in there, what are you usually doing? Reading? Then maybe a small reading journal (listing books you want to read or have read, if you have trouble keeping track, like me), reading glasses if you need them, Post-Its. Or: a few magazines, small notepad/pen if there's a phone in that room, a small tube of hand cream.

Now those are in the "usefuls" department.

You can create a "tablescape" kind of thing by using, say, a collection of flat-backed paperweights ("millefleur" type comes to mind -- google it), the little glass pebbles that have interesting sayings carved into them (like "Simplify"). Maybe you've collected small toys like mini Rubik's Cubes over the years--hey, I'm just trying to get your imagination going!--put them in there to play with. Maybe a bundle of dried flowers (like lavender)?

For the cloth topper itself: Find a fabric store and wander around the decorative cloth section (where they have the extra-long bolts for curtains, upholstery) and the quilting fabric section. Or if you like lacy stuff, you'll probably find that. There are many interesting patterns. You can easily hem the edges either with hand-stitching or an iron-on fusible webbing (just tell a clerk what you are planning and he/she will know what you need).

Cloth topper - I've found the oversized cloth napkins that come in a multitude of colors, fabrics, textures, prints, etc. at places like BBB, TJ Maxx, Homegoods, etc. to be a perfect fit when placed on the angle.

As for a tray - if I wanted it functional I would stack current magazines/books, have a small dish for candies or nuts or whatever, and a plant or decorative candle or even a small folded throw.

If not so functional, then things that compliment the room's decor. Candlescape, plantscape, collection items...

Jars, hurricanes, terrariums full of unexpected items always catch my eye.

Google "tablescapes" and scale down just about anything you see & like. :)

Thank you all for the ideas and suggestions. I do like the look of the cloth on the table and will search for the right cloth. Also the ideas for the tray are great.
Thanks, Peppygirl