MTG Salvation

So... you can tap an equipment to get a big cost-efficient body with evasion that dodges the commander tax, undermining any attempts to kill it.

I really doubt that it would be competitive but a mono-blue voltron deck sounds fun.

It won't dodge the Commander Tax as the tax is an additional cost. This oracle text is pretty far off and likely should read "You may pay 3U and tap an artifact you control rather than pay Zahid, Djinn of the Lamp's mana cost." Spells having their mana cost replaced with alternative costs, like Zombie commanders with Rooftop Storm, still will need to pay any mandatory additional costs, of which the Commander Tax is one.

Doesn't dodge commander tax entirely, but I would say he is still worth consideration. 3U for a 5/6 with evasion on the first cast is well above curve for a beater for something like a control-voltron build. As what a lot of voltron builds tend to lack is access to blue which gives you stuff like counterspell or cyclonic rift.

an artifact like Mox Amber

This guy and Heart of Kiran or Hope of Ghirapur could be good in standard. He doesn't die to Fatal Push and with the new Mox Amber you could get him very early.

Zahid should be fun with Mox Amber and other assorted low-cmc/no-cmc utility artifacts. Mahamoti Djinn for 3U is legit. Should be playable in a variety of decks. I suspect control might be looking for something a little more versatile/cantrippy, but tempo and/or more aggressive midrange decks should be happy to try to him out.

Equipment still works when tapped.

Hmm...

Not everyday you get a creature that already has it's own theme music https://www.youtube.com/watch?v=XUhVCoTsBaM

HAIL 2 U!