Amazon.com: Strictly Briks Classic Big Briks Circle Baseplate 100% Compatible with All Major Brands | Large Pegs for Toddlers | 12.5" Diameter Building Brick Base | Green Tight Fit Stackable Base Plate :
BrickLink - Part 11213 : LEGO Plate, Round 6 x 6 with Hole [Plate, Round] - BrickLink Reference Catalog
LEGO Part Reddish Brown Plate, Round 1 x 2 with Two Open Studs - Brick Land
LEGO Black Plate 1 x 1 Round (6141) | Brick Owl - LEGO Marketplace
LEGO® 11213 6109817
LEGO part 4073 - Dark Purple Plate, Round 1 x 1 Straight Side at BrickScout
Amazon.com: Pixel Bricks Mosaic Art Pieces Compatible with Lego, 1x1 Round Plate 100 Pieces 4073 / 6141 Brick, 40+ Colors Available (325-Lavender) : Everything Else