I’m waiting for these three stickers to arrive.
I found them on a site unbeknownst to me until that date, called redbubble.com

I only paid around €6,- for the lot of them, because I ordered six in total.
The site also offers t-shirts with the same motifs. 

Here are the links should you be interested:

“Engage” — “Live long and… Brains!!” — “Are you out of your Vulcan Mind?”