This is the year of the add-on badge at conferences. They're using a brand new standard with the unfortunate name "Shitty Add-Ons": https://hackaday.io/project/52950-defcon-26-shitty-add-ons

Look around and you'll find a ton of them on Hackaday.io, most are already on the Conference Badge list (but ask Rich Hogben if yours still needs to be added): https://hackaday.io/list/25935-conference-badges

A bunch of these have popped up on Tindie. Here's some that I've come across already:

Trash Panda linked above: https://www.tindie.com/products/brandon-satrom/badgelife-trash-panda-standalone-badge/

TwinkleTwinkle store has six addons: https://www.tindie.com/stores/twinkletwinkie/

Futurama add-on set: https://www.tindie.com/products/sqearlsalazar/sqearlsalazar-badgelife-add-on-set/

AND!XOR hypnotoad: https://www.tindie.com/products/andnxor/badgelife-toad-add-on-kit/

If you know of more, add them here as comments.