You can try getting a digital key from one of the many key codes websites! You can check the likes of humblebundle.com, greenmangaming.com, and fanatical.com (three websites I personally recommend and use frequently) for key codes of games you’d like to gift. Just keep in mind, they also sell games for other game redemption stores, so make sure the game your purchasing is redeemed ON STEAM before purchase. Also, the code is provided digitally only, so you’ll need to print it out, write it in a card, email it, etc.

Then, the gift receiver just needs to redeem the key in Steam to have the game added to their library.