I'm a big fan of Fun retros, and I like smuggling my doodles into my work*.
If your retrospectives feel a bit repetitive or you're working with a team you don't know well and want to learn a bit more about them before you hit the ground, check out Hot-air Balloon, Bad Weather. It's quite versatile and works well with remote setups.
And, feel free to use the template I made!
It should work fine as a background for Mural, Miro, Figma Jam board or whatever is your jam (fig's mine).
* There's still a bunch of businesses in the Square Mile with ponies hidden in their documentation. The more JIRA you use, the more ponies you get.
PS. Speaking of facilitation materials, if you're looking for something less developer-oriented check out the Hyper Island Toolbox.