Enzan's are left in the Nexus in some cases, at the door of where they live if he knows where and can get there. If anyone does see him leave them, he's wearing a little Santa hat.
To Netto-chan: A blue butterfly barrette edged with diamonds. The spots on the antennae are tiny Hikari symbols.
To his older alt and Blues: Several movies he thinks they'd like, mostly comedies, and directions to his world's portal and his house if they ever need his help.
To his younger alt: A box full of battlechips, mostly swords but a handful of strong recoveries as well. Plus a scribbled note with personal recommendations.
To Netto: A magazine full of the latest news on Netbattle strategy and Navi customizing.
To V2: Packages of hair ties in varying colors. He might know other Enzans like hair braiding and he might not.
To younger Netto-chan: A poetry book with tags sticking out recommending certain ones, and all the poems were written by high-school students. It was probably printed a few years back, around the time Enzan was in high school.
To all his other alts: Sets of battlechips of varying types. For his Dark Blues-era alt, a note of encouragement with them.
To other Blueses he's met: Joke books. Presumably to cheer either them or their Enzans.
For Meiru: A tiny snowglobe of Densan city. There's a little penguin in the middle. He leaves it with her mother since she's not there.
For Tohru: One part of a set of super long-range walkie-talkies.
Blues-chan's are left wherever she's certain they'll reach their reciever. She's not wearing anything really special, despite her Enzan's protests she should put on a Santa hat or something.
To V2: She'd love to give him this in person, but would probably be too embarrassed to. It's a booklet full of her notes and observations on everything in the Nexus and many things in her world. All of it, of course, is tinted with a personal and emotional flavor and narrative that makes it seem like a story.
To the younger Enzan: A note of apology for her own Enzan's attitude, and some guaranteed LOL-free brownies with peanut butter for icing.
To the older Enzan: A note of apology for her own behavior, as well as one of profuse thanks for taking care of her Enzan. There's a box of chocolates that the notes are attached to.
To her alt: Another note of thanks for helping her Enzan and a box of those crystallized candy fruits with sugar on them.
To her Navi friends: .mp3 format Christmas carols
To her Navi friends' operators: Socks with reindeer and elves on them
To other Nexusites she's met and liked: Nothing special, maybe a bag of Christmas candies.
You can say your character saw them or not, or use whatever methods you want to say the gifts got there. You can post here if you want to interact with them, but otherwise you don't have to.
Merry Christmas, everyone!