In the New York Magician series, Michel is able to pull a magical flintlock pistol out of the air by raising his arm like he's hailing a cab.
The Legend of Neil (a Legend of Zelda parody) inverts this then lampshades it. For the first few episodes Neil awkwardly carries everything (including bomb, bow, sword, shield, and the raft) until a secret Moblin teaches him how to use hammerspace.
Played Straight in Metafictionized Phlebotinum Poisoning, where Arthur explains that the angels get 'P.L.O.T. hole' lockers, which are just regular storage units, but with mini-portals attached. Also explains how he drew his sword out of nowhere. Tagino gets one in chapter seven, too.
Lampshaded in Four Swords Misadventures episode 7 when Green reacts with confusion when a drunken Red manages to use a hookshot on Dark Link after being inadvertantly woken up by him (he earlier passed out), with Blue asking Green "how should [Blue] know [where Red got the Hookshot]?" after Green asked him.
"I will now use the Millennium Rod, which I keep clenched between my buttocks, to send this duel to the shadow realm!"
In the Whateley Universe, there's a character codenamed Mobius who makes utility belts with pouches that are about ten times bigger in each direction than they are on the outside. Phase has one that looks like it couldn't hold a postage stamp. He carries everything up to a touch Taser and throwing knives in it.
In Dr. Horrible's Sing-Along Blog, after the eponymous character spends time walking around monologuing, he suddenly spins around and dramatically pulls out from under his lab coat a giant Death Ray that was quite clearly not actually under there before that point due to the way the coat hangs. note Confirmed in the commentary, where they note that they filmed the scene in two parts, "pre-gun" and "post-gun".
The hammer space is his penis
In this Conroy Cat short where Conroy pulls out several items throughout the cartoon that will help him from stop falling.
Invoked by Daniel in "On The Couch", who hides large weapons in convenient places in Curly's house.
When transformed, the characters in The Cartoon Man are able to produce cartoon objects from thin air. Simon pulls out an actual hammer on multiple occasions.
SCP items labeled "ectoentropic" will likely implement this trope in some fashion since it means the object generates matter and/or energy in an anomalous manner.
In RWBY, Ruby and Yang's father sends them Zwei, the family corgi, by mail. Somehow, the dog recovers almost instantly from spending a goodly amount of time squished into a mail tube. That's not what makes this an example of hammerspace, though. That would be when Yang gives the tube a good shake, unloading a massive pile of dog food cans, plus a can opener.
In X-Ray and Vav, Hilda reveals that X-Ray and Vav's "overundies" are essentially utility belts connected to another dimension, giving them access to all sorts of gadgets. X-Ray, then, decides to have A Date with Rosie Palms.