Think of the 2025 Topps Series 1 Baseball Celebration Mega Box as a new twist on the retired Opening Day line. Instead of creating an entirely new product with a minimally different base set, this special box sticks with regular Series 1 cards and adds some exclusive inserts to make it different. Like Opening Day, the release of the Celebration Mega Box coincides with the start of the MLB regular season as well. 2025 Topps Series 1 Baseball Celebration Mega Box Checklist Overview Each 16-pack mega box has a lot of overlapping content from the main Series 1 release. This includes the 350-card base set plus inserts, autographs and memorabilia cards. But there’s more here that collectors won’t find in regular packs. This starts with Confetti parallels that cover the base set. These land 1:3 Celebration packs, which means there should be at least five per mega box. A staple of Topps Opening Day for several years were Mascot inserts. They make the jump over to flagship with a 25-card set that’s exclusive to Celebration boxes. Keeping with the theme are high-end Dynasty Mascot Autograph Patch cards. These have on-card signatures and premium swatches. Mascots aren’t the only inserts making the jump over from Opening Day. There’s also Walk This Way and Dugout Peeks. When Topps discontinued Opening Day, they shifted to Big League for similar content. 8-Bit Ballers and Gameday Drip. Power Players are some of the most colorful inserts of the year. Although not a direct recreation, these do have some similar elements to an insert set from 2000 Topps Baseball. Finally, rare Big Head Variations bring back a bobblehead sort of vibe (or caricature shirts for those of us who had Bash Brothers and Ken Griffey Jr. posters on our bedroom walls back in the early ’90s). 2025 Topps Series 1 Baseball Celebration Mega Box baseball cards at a glance: Cards per pack: 14Packs per box: 16Boxes per case: 20Set size: 350 cards (2025 Topps Series 1)Release date: March 26, 2025 Shop for 2025 Topps Series 1 Baseball Celebration boxes on eBay: Celebration Mega Box What to expect in a Celebration mega box: Exclusive Inserts – 16 Confetti Parallels – 5