A few basic optimizations really stand out to me. For example, swapping Workshop Assistant for the cheaper Myr Retriever or the flying Junk Diver. Etherium Sculptor over Jhoira's Familiar is another- though being fair the former doesn't discount non-artifact legendaries.

Unless you need it as a creature, Spine of Ish Sah is probably better than Meteor Golem especially as it synergizes as sacrifice-fuel, and can be tutored out with Arcum. It has the ability to also take down problematic lands if needed, like Fields of the Dead or a flipped Thaumatic Compass.

I'd also highly, HIGHLY recommend Master Transmuter - she's a wonderful addition, her worst case scenario is flickering your artifacts- getting an additional ETB out of them, by putting back down the same artifact you picked up. Her best is swapping a Sol Ring for a Darksteel Forge at instant-speed.

^Thanks for the advice! Most all of those cards are ones that I have laying around and have been in and out of my Rebbec/Glacian deck. I'll add them to the maybeboard and give them all another glance over the next time I make an update.