I got the idea from a thread on the MS Paint Adventures forum; a thread where people can post links to shout-outs and references to Foundation characters and objects.
Remember; coincidences don't count. It has to be clear that it's a deliberate reference to the Foundation in another work (coincidences probably go somewhere else).
To start off, the Painterly Pack for Minecraft includes SCP envelopes as an aleternative skin for monster eggs, and an SCP-173 Enderman skin.
Also, episode 14 of season 4 of the webseries Extra Credits (the most recent episode at the time of writing) has a "blink-and-you'll miss it" reference to SCP-914 around the 1:58 minute mark.