Perhaps you can relate: I use the second leaf in our dining room table about 2 to 3 times per year, extending the table to seat 8 or 10. Otherwise, we use the table with one leaf for seating for 6.
For Thanksgiving this year, we'll be using the extra leaf so we can maintain a smidge of extra distance between both parties (son and DIL plus 4 of us) while eating. With the 2 leaves installed, the surface dimensions are 44" wide by 84" long. A table cloth should ideally have between 6 to 10 inches overhang. So, my table would need a cloth that is between 56" to 64" wide and between 96" to 104" long.
So here are some options:
thin cotton quilts -- the standard size of a quilt is 70" by 90". This would give me an overhang on the sides of 13 inches and on the ends of 3 inches. I used a pastel, thin cotton quilt for the table at a baby shower many years ago.
flat bed sheets (the top sheet) -- twin size sheets are typically 66" wide by 96" long. Twin extra-long (like what many dorm rooms at universities have) is the same width, 66", but 5-6 inches longer, 101" or 102". For my purposes, the extra-long would be preferable, as the top edge of a flat sheet has a differently-sewn finish than the other three sides. With an extra-long, I could fold this top edge under 6 inches and baste or duct tape this flap in place. When I set up a folding rectangular table outdoors, I often use flat bed sheets as the table cloth. With this particular table, because the legs are not terribly attractive, I use a wider sheet that almost comes to the ground on the overhang.
colorful wool or cotton blankets without the satin top edge -- twin size blankets are typically 65" buy 90". The width would work for my table and the length would allow a very small overhang on the ends of 3 inches each end. I've used colorful cotton throws positioned on the diagonal as a table topper before. This can look especially attractive for a festive dinner, such as Cinco de Mayo.
fabric yardage -- any fabric yardage that is 60 inches wide works for my table. With fabric I already own and don't want to cut to size on the length, I can fold under one or both ends to achieve the ideal overhang on ends. Don't many of us have a stash of fabric waiting to be sewn into something special?
wrapping paper roll -- the standard width of a roll of wrapping paper is 30 inches. The length varies, but many are between 96 and 100 inches long. Two rolls of paper can be slightly overlapped and taped on the underside, creating a near invisible seam down the center of the table. The fun thing about using wrapping paper is that you can customize it to the celebration. In addition to colorful gift wrap, brown craft paper is also an option. After the meal, unspoiled portions of the wrap can be rolled back up and used for gift-wrapping later. This is especially fun for a child's birthday party. I used craft paper for my son's 3rd birthday and gave all the kids crayons to decorate their places at the table.
curtains, rod pocket or clip hang variety, not pinch pleat-- rod pocket and clip hang curtain panels come in a variety of sizes. Common widths for panels include 48 inches, 56 inches, 58 inches, and 60 inches. Standard lengths are 63", 84", 96", 108", and 120". The 48' width would be too narrow for my table, but the other three widths would work. A lace panel would be pretty on a dining table. A lace curtain panel is on my "seek" list for thrift stores and garage sales.
canvas painter's drop cloth -- drop cloths come in a variety of sizes. The 6 ft by 9 ft (72" by 108") would work on my table, with longer overhangs along the sides (14 inches overhang along each side). Pinterest is full of inspiration for turning a canvas drop cloth into a table cloth. I love this look. I saw an especially pretty table topper that was made from a drop cloth. The owner fitted the cloth to the top of the table with a short overhang all around. Then around the bottom edge, she added a ruffle of the canvas. It had a shabby chic sort of look.
if the table surface is in good condition, placemats work very well and most of us have several. Ditto on table runners -- any fabric yardage can become a runner by folding the two long sides under to make the runner's width equal about 1/3 of the table's width. For most of my growing up years, my mother used delicate straw placemats on this same table.
My dining room table was my parents (bought in 1966) and has quite a bit of wear. I prefer to cover it with a cloth to conceal this wear. For Thanksgiving, I've chosen to use a 3.5 yard length of dark plaid wool yardage from my sewing supplies. For many years, I've intended to sew something for myself with this wool. I will someday. For now, it makes the perfect Thanksgiving table cloth for my extra long table, with its dark colors harmonizing with my brown transfer ware dishes. The side edges already have a selvedge finish, so there are no hanging threads. I've folded about 18 inches under at one and of the table to make the length of fabric fit.
Obviously, the best table cloth for 2 uses per year is something I already own, can obtain inexpensively, or can be reused for another purpose. I likely wouldn't go out and retail-purchase a curtain panel or extra-long twin flat sheet if I couldn't use them other than as a table cloth 2 times per year, especially since I could just buy an actual table cloth that fits for the same price. However, I might buy any of the above items at a thrift store or garage/estate sale, if the price was right and the measurements worked for our table. I would buy wrapping paper, craft paper, or a canvas drop cloth to use again afterward for wrapping or painting, if I was needing items for those purposes.
How about you? Have you used sheets or other unconventional coverings as tablecloths?