YubiKeys! https://www.yubico.com/ a tool to increase your security. But can be expensive.
His/her favourite programming language or tool as a mug/sticker/tshirt on redbubble.com
Some cool mug that automatically warms up or stirs with a button. Because techies need coffee.
Laptop webcam blocker sticker/shuffle to keep ur privacy.
LED stuff. Like a led strip or something because cool lights are nice.
Smarthome stuff like a smart plug! It shows power usage of devices and u can program it using automations with homeassistant https://www.tp-link.com/en/home-networking/smart-plug/hs110/ - cool to automate ur home with it.