At least as far back as 2009, Hallmark has produced limited edition comicon exclusive ornaments for SDCC and NYCC. These are typically repainted redux of a previously mass-released ornament, reusing an existing mold.
I get most of my specifics on Hallmark Star Trek ornaments from the wordpress blog, Hallmark Star Trek Ornaments (HSTO). Also, images in this post are screen captures from various online sale sites.
A redux of Uhura apparently started the Star Trek comic con releases. When I started gathering for ST:TCT, I saw one yellow Uhura listed for maybe $250 and I was gobsmacked. With the current price above, and the fact that I’ve not seen a listing since, I regret not getting it.
According to HSTO, this 2009 SDCC exclusive had a limited edition of 450.
This is likely the coolest repaint for a comic con exclusive. The glow-in-the-dark paint evoking the interphased glow of the USS Defiant from ST:TOS episode The Tholian Web.
This one had a record of sale a few years ago at $350, without any live listings. According to HSTO, this 2011 NYCC event exclusive had a limited edition of 700.
The battle-damaged Kelvin (from the JJ Abrams reboot movies) is a repaint of the general-release Kelvin of the same year.
According to HSTO, this was a 2013 SDCC and NYCC event exclusive in a limited edition of 1,575 copies.
The 2016 exclusive was a painted version of the gold anniversary Enterprise from the same year.
According to HSTO, this was a 2016 SDCC, NYCC, and ST: Mission New York event exclusive in a limited edition of 3,450 copies.
Arex and M’Ress was released after we started ST:TCT, so I found a set immediately following SDCC. Just after release, exclusives can be found listed anywhere around 1.5-2x the original price. Considering the costs to attend SDCC, I consider this an acceptable price.
HSTO lists this one as a 2018 SDCC, NYCC, and the Official ST Convention (in Vegas) event exclusive in a limited edition of 2,800.
For the ISS Enterprise, I nearly succeeded in establishing a comic con attending network. I did establish it for future event exclusive and found one online for an acceptable markup, significantly lower than the price above.
This year’s event exclusive is a redux of 2019’s tribble, produced with a different color faux fur. When the cons went virtual, plans were announced for an online exclusive event. I found the ornament on auction listings before I found specifics about the event.
I understand the extreme price jumps are the rarer ornaments over the past few years. CBS has released three new shows in the franchise, with plans for an additional three shows.
What makes me sad about these auction listings: I appreciate Hallmark’s shout-out to the fandom with the event exclusives, but it turns into sellers buying them up for price-gouging later. So the world works, I suppose… but it does make me sad.
If anyone reading this comes across a glow-in-the-dark Constitution class starship in some random bargain bin or estate sale, consider sending it my way…
our cattywampus cottage 
I run into the same issues with my DC Comics figures. I have the Flashpoint set (Aquaman, Wonder Woman, & Batman from that alternate timeline) and Flashpoint Cyborg. Flashpoint Reverse Flash, however, was an SDCC con exclusive and the few I found were outrageously priced. So I feel your pain.