Do you know what makes your houseplants look great? Beautiful pottery.
It doesn’t have to be expensive. And it doesn’t have to match.
However, it does help if the saucer is big enough to catch overflow from watering and it really should be glazed (good if it’s on the inside only, great if it’s on both inside and outside) to protect the surfaces where you set your potted plants.
Back to it not being expensive, the lovely ceramics above are from Japan and range from $1.50 to $3.00 in the U.S. in Daiso stores (they’re like Japanese “dollar stores”). Sure, they’re great for food, but they look gorgeous and bohemian with potted plants! If you don’t have a Daiso store near you, try plundering a thrift store for some chic or offbeat china.
And about not matching? There’s no rule that says pots have to match their saucers (I checked). Again with the bohemian! Yes, it gives an eclectic, eccentric, collected-over-time look if you mix-and-match your pottery. Think of it as dressing up your plants in outfits. You want things to complement each other, not match.