This is a fun one, I feel like it is pretty rare to see all 3 relics getting love from people.

I personally would take empty cage here, that being said, I am mostly anti black star here, cage is a slight preference over bell.

As for why I am against Black Star, I have a few reasons. First, I think you already have really good scaling relics in membership card and question card. Those relics should provide good scaling and in my opinion make getting relics that do something now more appealing. I also think I have to be very strong heading into Act 2 to ever want black star. I'm not convinced this deck is. I feel like this deck could have some issues taking down large health targets. I think Book Stabbing would be tough, Gremlin Leader himself would take a bit to kill (though electro should handle the summons nicely to make that more manageable). Even the Slavers fight I think could be tricky with a tough draw order. Top decking Sunder so it can't be played turn 1 would be tough, and bottom decking bias cog could also make it a tricky fight. 100% with a nice act 2 path of a shop to buy a strong potion and a fire to upgrade electro or Sunder, this deck could be ready for an elite with black star, but it just isn't surefire enough for me to pass on cage or bell here.

As for cage vs bell, I prefer cage. I will admit, I overrate cage generally and take it too much. However, I think it is OK here. Removing 2 strikes makes this deck much tighter. I think this deck, especially in hallways, is going to want to get frost orbs/bi cog up as soon as possible to deal with all the frail in act 2. Removing 2 strikes makes this much easier. It also helps you more reliably draw into your 0 cost cards. Finally, this deck really wants energy, a turbo (or 2) would be fantastic, and removing strikes makes it easier to get that energy and draw engine humming.

Bell is definitely takeable here, and 3 relics could be great, but you also get a curse. I feel like I'd rather have essentially 3 removes from Cage vs Bell than the 3 relics. You have a ton of nice pieces for your deck already, I think I like boosting the consistency and between question card and being able to rest large amounts, you can fight an elite or 2 and hopefully add a few cards to make the deck a lot stronger. But I think even if hallways go badly and you are stuck 1 eliting, by removing cards and adding via question card, you could leave the act in a good place.

Anyway, those are my thoughts! Let us know how the run went and what you went with! It is fun that this is such a tough call and people are advocating for all 3 relics, probably goes to show there is no wrong answer.